Manticore Documentation

Welcome to Manticore Search’s Documentation

Introduction

About

Manticore Search is a full-text search engine, publicly distributed under GPL version 2, forked from 2.3 branch of open-source search engine Sphinx search.

Technically, Manticore is a standalone software package provides fast and relevant full-text search functionality to client applications. It was specially designed to integrate well with SQL databases storing the data, and to be easily accessed by scripting languages. However, Manticore does not depend on nor require any specific database to function.

Applications can access Manticore search daemon (searchd) using any of the following access methods: - Manticore own implementation of MySQL network protocol (using a small SQL subset called SphinxQL, this is recommended way) - native search API (SphinxAPI) - HTTP protocol - via MySQL server with a pluggable storage engine (SphinxSE).

Official native SphinxAPI implementations for PHP, Perl, Python, Ruby and Java are included within the distribution package. API is very lightweight so porting it to a new language is known to take a few hours or days. Third party API ports and plugins exist for Perl, C#, Haskell, Ruby-on-Rails, and possibly other languages and frameworks.

Manticore supports two different indexing backends: “disk” index backend, and “realtime” (RT) index backend. Disk indexes support online full-text index rebuilds, but online updates can only be done on non-text (attribute) data. RT indexes additionally allow for online full-text index updates.

Data can be loaded into disk indexes using a so-called data source. Built-in sources can fetch data directly from MySQL, PostgreSQL, MSSQL, ODBC compliant database (Oracle, etc) or from a pipe in TSV or XML format. Adding new data sources drivers (eg. to natively support other DBMSes) is designed to be as easy as possible. RT indexes can only be populated using SphinxQL.

Manticore features

Key Manticore features are:

  • high indexing and searching performance;
  • advanced indexing and querying tools (flexible and feature-rich text tokenizer, querying language, several different ranking modes, etc);
  • advanced result set post-processing (SELECT with expressions, WHERE, ORDER BY, GROUP BY, HAVING etc over text search results);
  • proven scalability up to billions of documents, terabytes of data, and thousands of queries per second;
  • easy integration with SQL and XML data sources, and SphinxQL, SphinxAPI, or SphinxSE search interfaces;
  • easy scaling with distributed searches.

To expand a bit, Manticore:

  • has high indexing speed (upto 10-15 MB/sec per core on an internal benchmark);
  • has high search speed (upto 150-250 queries/sec per core against 1,000,000 documents, 1.2 GB of data on an internal benchmark);
  • has high scalability (biggest known cluster indexes over 3,000,000,000 documents, and busiest one peaks over 50,000,000 queries/day);
  • provides good relevance ranking through combination of phrase proximity ranking and statistical (BM25) ranking;
  • provides distributed searching capabilities;
  • provides prospective searches (percolate queries)
  • provides document excerpts (snippets) generation;
  • provides searching from within application with SphinxQL or SphinxAPI interfaces, and from within MySQL with pluggable SphinxSE storage engine;
  • supports boolean, phrase, word proximity and other types of queries;
  • supports multiple full-text fields per document (upto 32 by default);
  • supports multiple additional attributes per document (ie. groups, timestamps, etc);
  • supports stopwords;
  • supports morphological word forms dictionaries;
  • supports tokenizing exceptions;
  • supports UTF-8 encoding;
  • supports stemming (stemmers for English, Russian, Czech and Arabic are built-in; and stemmers for French, Spanish, Portuguese, Italian, Romanian, German, Dutch, Swedish, Norwegian, Danish, Finnish, Hungarian, are available by building third party libstemmer library);
  • supports MySQL natively (all types of tables, including MyISAM, InnoDB, NDB, Archive, etc are supported);
  • supports PostgreSQL natively;
  • supports ODBC compliant databases (MS SQL, Oracle, etc) natively;
  • …has 50+ other features not listed here, refer configuration manual!

Where to get Manticore

Manticore is available through its official Web site at http://manticoresearch.com/.

Currently, Manticore distribution tarball includes the following software:

  • indexer: an utility which creates fulltext indexes;
  • searchd: a daemon which enables external software (eg. Web applications) to search through fulltext indexes;
  • sphinxapi: a set of searchd client API libraries for popular Web scripting languages (PHP, Python, Perl, Ruby).
  • spelldump: a simple command-line tool to extract the items from an ispell or MySpell (as bundled with OpenOffice) format dictionary to help customize your index, for use with wordforms.
  • indextool: an utility to dump miscellaneous debug information about the index
  • wordbreaker: an utility to break down compound words into separate words

License

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. See COPYING file for details.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

Credits

Manticore is derived from Sphinx search engine created by Andrew Aksyonoff. More details about people involved in Sphinx development can be found on this page: http://sphinxsearch.com/docs/devel.html#credits.

Manticore is developed and maintained by Manticore Software Ltd. Current team (in alphabetical order):

  • Adrian Nuta
  • Alexey Vinogradov
  • Gloria Vinogradova
  • Ilya Kuznetsov
  • Mindaugas Zukas
  • Sergey Nikolaev
  • Stanislav Klinov

Installation

Installing Manticore packages on Debian and Ubuntu

Supported releases:

  • Debian

    • 7.0 (wheezy)
    • 8.0 (jessie)
    • 9.0 (stretch)
  • Ubuntu

    • 14.04 LTS (trusty)
    • 16.05 LTS (xenial)

Supported platforms:

  • x86
  • x86_64

You can install Manticore with command:

$ wget https://github.com/manticoresoftware/manticore/releases/download/2.4.1/manticore_2.4.1-171017-3b31a97-release-stemmer.jessie_amd64-bin.deb
$ sudo dpkg -i manticore_2.4.1-171017-3b31a97-release-stemmer.jessie_amd64-bin.deb

Manticore requires no extra libraries to be installed on Debian/Ubuntu. However if you plan to use ‘indexer’ tool to create indexes from different sources, you’ll need to install appropriate client libraries. To know what exactly libraries, run indexer tool from Manticore and look at the top of it’s output:

$ indexer
Manticore 2.4.1 4258276@171019 id64-beta
Copyright (c) 2001-2016, Andrew Aksyonoff
Copyright (c) 2008-2016, Sphinx Technologies Inc (http://sphinxsearch.com)
Copyright (c) 2017, Manticore Software LTD (http://manticoresearch.com)

Built by gcc/clang v 6.3.0,

Built on Linux d2a57137d4f5 4.8.0-45-generic #48~16.04.1-Ubuntu SMP Fri Mar 24 12:46:56 UTC 2017 x86_64 GNU/Linux
Configured by CMake with these definitions: -DCMAKE_BUILD_TYPE=RelWithDebInfo -DDL_UNIXODBC=1 -DUNIXODBC_LIB=libodbc.so.2 -DDL_EXPAT=1 -DEXPAT_LIB=libexpat.so.1 -DDL_MYSQL=1 -DMYSQL_LIB=libmariadbclient.so.18 -DMYSQL_CONFIG_EXECUTABLE=/usr/bin/mysql_config -DDL_PGSQL=1 -DPGSQL_LIB=libpq.so.5 -DSPLIT_SYMBOLS=ON -DUSE_BISON=ON -DUSE_FLEX=ON -DUSE_SYSLOG=1 -DWITH_EXPAT=ON -DWITH_ICONV=ON -DWITH_MYSQL=ON -DWITH_ODBC=ON -DWITH_PGSQL=ON -DWITH_RE2=ON -DWITH_STEMMER=ON -DWITH_ZLIB=ON

Here you can see mentions of libodbc.so.2, libexpat.so.1, libmariadbclient.so.18, and libpq.so.5.

Below is the reference table with list of all client libraries for different debian/ubuntu distributions:

Distr Mysql PostgresQL Xmlpipe Unixodbc
trusty libmysqlclient.so.18 libpq.so.5 libexpat.so.1 libodbc.so.1
xenial libmysqlclient.so.20 libpq.so.5 libexpat.so.1 libodbc.so.2
wheezy libmysqlclient.so.18 libpq.so.5 libexpat.so.1 libodbc.so.1
jessie libmysqlclient.so.18 libpq.so.5 libexpat.so.1 libodbc.so.2
stretch libmariadbclient.so.18 libpq.so.5 libexpat.so.1 libodbc.so.2

To find the packages which provide the libraries you can use, for example apt-file:

$ apt-file find libmysqlclient.so.20
libmysqlclient20: /usr/lib/x86_64-linux-gnu/libmysqlclient.so.20
libmysqlclient20: /usr/lib/x86_64-linux-gnu/libmysqlclient.so.20.2.0
libmysqlclient20: /usr/lib/x86_64-linux-gnu/libmysqlclient.so.20.3.6

Note, that you need only libs for types of sources you’re going to use. So if you plan to make indexes only from mysql source, then install only lib for mysql client (in case above - libmysqlclient20).

Finally install necessary packages:

$ sudo apt-get install libmysqlclient20 libodbc1 libpq5 libexpat1

If you aren’t going to use indexer tool at all, you don’t need find and install any libraries.

After preparing configuration file (see Quick tour), you can start searchd daemon:

$ systemctl manticore start

Installing Manticore packages on RedHat and CentOS

Supported releases:

  • CentOS 6 and RHEL 6
  • CentOS 7 and RHEL 7

Supported platforms:

  • x86
  • x86_64

Manticore requires no extra libraries to be installed on RedHat/CentOS. However if you plan to use ‘indexer’ tool to create indexes from different sources, you’ll need to install appropriate client libraries. Use yum to download and install these dependencies:

$ yum install mysql-libs postgresql-libs expat unixODBC

Note, that you need only libs for types of sources you’re going to use. So if you plan to make indexes only from mysql source, then installing ‘mysql-libs’ will be enough. If you don’t going to use ‘indexer’ tool at all, you don’t need to install these packages. Download RedHat RPM from Manticore website and install it:

$ wget https://github.com/manticoresoftware/manticore/releases/download/2.4.1/manticore-2.4.1-171017-3b31a97-release-stemmer-rhel7-bin.rpm
$ rpm -Uhv manticore-2.4.1-171017-3b31a97-release-stemmer-rhel7-bin.rpm

After preparing configuration file (see Quick tour), you can start searchd daemon:

$ systemctl searchd start

Installing Manticore on Windows

To install on Windows, you need to download the zip package and unpack it first.

cd C:\Manticore
unzip manticore-2.4.1-171017-3b31a97-release-pgsql-stemmer-x64-bin.zip

Edit the contents of sphinx.conf.in - specifically entries relating to @CONFDIR@ - to paths suitable for your system.

Install the searchd system as a Windows service:

C:\Manticore\bin> C:\Manticore\bin\searchd --install --config C:\Manticore\sphinx.conf.in --servicename Manticore
  1. The searchd service will now be listed in the Services panel within the Management Console, available from Administrative Tools. It will not have been started, as you will need to configure it and build your indexes with indexer before starting the service. A guide to do this can be found under Quick tour.

Compiling Manticore from source

Required tools

  • a working compiler

    • on Linux - GNU gcc (4.7.2 and above) or clang can be used
    • on Windows - Microsoft Visual Studio 2015 and above (community edition is enough)
    • on Mac OS - XCode
  • cmake - used on all plaftorms (version 2.8 or above)

Optional dependencies

  • git, flex, bison - needed if the sources are from cloned repository and not the source tarball
  • development version of MySQL client for MySQL source driver
  • development version of unixODBC for the unixODBC source driver
  • development version of libPQ for the PostgreSQL source driver
  • development version of libexpat for the XMLpipe source driver
  • RE2 (bundled in the source tarball) for regexp_filter feature
  • lib stemmer (bundled in the source tarball ) for additional language stemmers

General building options

For compiling latest version of Manticore, recommended is checkout the latest code from the github repositiory. Alternative, for compiling a certain version, you can either checked that version from github or use it’s respective source tarball. In last case avoid to use automatic tarballs from github (named there as ‘Source code’), but use provided files as manticore-2.4.1-171017-3b31a97-release.tar.gz. When building from clone you need packages git, flex, bison. When building from tarball they are not necessary. This requirement may be essential to build on Windows.

$ git clone https://github.com/manticoresoftware/manticore.git
$ wget https://github.com/manticoresoftware/manticore/releases/download/2.4.1/manticore-2.4.1-171017-3b31a97-release.tar.gz
$ tar zcvf manticore-2.4.1-171017-3b31a97-release.tar.gz

Next step is to configure the building with cmake. Available list of configuration options:

  • CMAKE_BUILD_TYPE - can be Debug , Release , MinSizeRel and RelWithDebInfo (default).

  • SPLIT_SYMBOLS (bool) - specify whenever to create separate files with debugging symbols. In the default build type,RelWithDebInfo, the binaries include the debug symbols. With this option specified, the binaries will be stripped of the debug symbols , which will be put in separate files

  • USE_BISON, USE_FLEX (bool) - enabled by default, specifies whenever to enable bison and flex tools

  • LIBS_BUNDLE - filepath to a folder with different libraries. This is mostly relevant for Windows building

  • WITH_STEMMER (bool) - specifies if the build should include the libstemmer library. The library is searched in several places, starting with

    • libstemmer_c folder in the source directory
    • common system path. Please note that in this case, the linking is dynamic and libstemmer should be available system-wide on the installed systems
    • libstemmer_c.tgz in LIBS_BUNDLE folder.
    • download from snowball project website. This is done by cmake and no additional tool is required
    • NOTE: if you have libstemmer in the system, but still want to use static version, say, to build a binary for a system without such lib, provide WITH_STEMMER_FORCE_STATIC=1 in advance.
  • WITH_RE2 (bool) - specifies if the build should include the RE2 library. The library can be taken from the following locations:

    • in the folder specified by WITH_RE2_ROOT parameters
    • in libre2 folder of the Manticore sources
    • system wide search, while first looking for headers specified by WITH_RE2_INCLUDES folder and the lib files in WITH_RE2_LIBS folder
    • check presence of master.zip in the LIBS_BUNDLE folder
    • Download from https://github.com/manticoresoftware/re2/archive/master.zip
    • NOTE: if you have RE2 in the system, but still want to use static version, say, to build a binary for a system without such lib, provide WITH_RE2_FORCE_STATIC=1 in advance.
  • WITH_EXPAT (bool) enabled compiling with libexpat, used XMLpipe source driver

  • WITH_MYSQL (bool) enabled compiling with MySQL client library, used by MySQL source driver. Additional parameters WITH_MYSQL_ROOT, WITH_MYSQL_LIBS and WITH_MYSQL_INCLUDES can be used for custom MySQL files

  • WITH_ODBC (bool) enabled compiling with ODBC client library, used by ODBC source driver

  • WITH_PGSQL (bool) enabled compiling with PostgreSQL client library, used by PostgreSQL source driver

  • DISTR_BUILD - in case the target is packaging, it specifies the target operating system. Supported values are: centos6, centos7, wheezy, jessie, stretch, trusty, xenial, macos, default.

Compiling on UNIX systems

To install all dependencies on Debian/Ubuntu:

$ apt-get install build-essential cmake unixodbc-dev libpq-dev libexpat-dev libmysqlclient-dev git flex bison

Note: on Debian 9 (stretch) package libmysqlclient-dev is absent. Use default-libmysqlclient-dev there instead.

To install all dependencies on CentOS/RHEL:

$ yum install gcc gcc-c++ make cmake mysql-devel expat-devel postgresql-devel unixODBC-devel rpm-build systemd-units git flex bison

(git, flex, bison doesn’t necessary if you build from tarball)

RHEL/CentOS 6 ship with a old version of the gcc compiler, which doesn’t support -std=c++11 flag, for compiling use devtools repository:

$ wget http://people.centos.org/tru/devtools-2/devtools-2.repo -O /etc/yum.repos.d/devtools-2.repo
$ yum upgrade -y
$ yum install -y devtoolset-2-gcc devtoolset-2-binutils devtoolset-2-gcc-c++
$ export PATH=/opt/rh/devtoolset-2/root/usr/bin:$PATH

Manticore uses cmake for building. We recommend to use a folder outside the sources to keep them clean.

$ mkdir build
$ cd build
$ cmake -D WITH_MYSQL=1 -DWITH_RE2=1 ../manticore

or if we use sources from tarball:

$ cmake -D WITH_MYSQL=1 -DWITH_RE2=1 ../manticore-2.4.1-171017-3b31a97-release

To simply compile:

$ make -j4

This will create the binary files, however we want to either install Manticore or more convenient to create a package. To install just do

$ make -j4 install

For packaging use package

$ make -j4 package

By default, if no operating system was targeted, package will create only a zip with the binaries. If, for example, we want to create a deb package for Debian Jessie, we need to specify to cmake the DISTR_BUILD parameter:

$ cmake -DDISTR_BUILD=jessie ../manticore
$ make -j4 package

This will create 2 deb packages, a manticore-x.x.x-bin.deb and a manticore-x.x.x-dbg.deb which contains the version with debug symbols. Another possible target is tarball , which create a tar.gz file from the sources.

Compiling on Windows

For building on Windows you need:

  • Visual Studio
  • Cmake for Windows
  • Expat, MySQL and PostgreSQL in bundle directory.

If you build from git clone, you also need to provide git, flex, bison tools. They may be fond in cygwin framework. When building from tarball these tools are not necessary.

For a simple building on x64:

C:\build>"%PROGRAMW6432%\CMake\bin\cmake.exe" -G "Visual Studio 14 Win64" -DLIBS_BUNDLE="C:\bundle" "C:\manticore"
C:\build>"%PROGRAMW6432%\CMake\bin\cmake.exe" -DWITH_PGSQL=1 -DWITH_RE2=1 -DWITH_STEMMER=1 .
C:\build>"%PROGRAMW6432%\CMake\bin\cmake.exe" --build . --target package --config RelWithDebInfo

Recompilation (update)

If you didn’t change path for sources and build, just move to you build folder and run:

cmake .
make clean
make

If by any reason it doesn’t work, you can delete file CMakeCache.txt located in build folder. After this step you have to run cmake again, pointing to source folder and configuring the options.

If it also doesn’t help, just wipe out your build folder and begin clean compiling from sources

Quick Manticore usage tour

We are going to use SphinxQL protocol as it’s the current recommended way and it’s also easy to play with. First we connect to Manticore with the normal MySQL client:

$ mysql -h0 -P9306

The default configuration comes with a sample Real-Time. A first step to see it in action is to add several documents to it, then you can start perform searches:

mysql> INSERT INTO rt VALUES (1, 'this is', 'a sample text', 11);
    Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO rt VALUES (2, 'some more', 'text here', 22);
    Query OK, 1 row affected (0.00 sec)

    mysql> INSERT INTO rt VALUES (3, 'more about this text', 'can be found in this text', 22);
    Query OK, 1 row affected (0.00 sec)
mysql> SELECT *,weight() FROM rt  WHERE MATCH('text') ORDER BY WEIGHT() DESC;
    +------+------+----------+
    | id   | gid  | weight() |
    +------+------+----------+
    |    3 |   22 |     2252 |
    |    1 |   11 |     1319 |
    |    2 |   22 |     1319 |
    +------+------+----------+
    3 rows in set (0.00 sec)

In the sample configuration there is also a plain index with MySQL source, which needs to be indexed first in order to start using it. First, we populate the sample table in MySQL:

mysql> create database test;
$ mysql -u test <  /usr/share/doc/manticore/example-conf/example.sql

The sample config uses a test with no password for connecting to MySQL. Adjust the credentials, then index:

$ sudo -u manticore indexer -c /etc/sphinxsearch/sphinx.conf test1 --rotate
Manticore 2.3.3 9b7033e@170806 master...origin/master-id64-dev
Copyright (c) 2001-2016, Andrew Aksyonoff
Copyright (c) 2008-2016, Sphinx Technologies Inc (http://sphinxsearch.com)
Copyright (c) 2017, Manticore Software LTD (http://manticoresearch.com)

using config file '/etc/sphinxsearch/sphinx.conf'...
indexing index 'test1'...
collected 4 docs, 0.0 MB
sorted 0.0 Mhits, 100.0% done
total 4 docs, 193 bytes
total 0.002 sec, 81503 bytes/sec, 1689.18 docs/sec
total 4 reads, 0.000 sec, 8.1 kb/call avg, 0.0 msec/call avg
total 12 writes, 0.000 sec, 0.1 kb/call avg, 0.0 msec/call avg
rotating indices: successfully sent SIGHUP to searchd (pid=2947).

Now let’s run several queries:

mysql> SELECT *, WEIGHT() FROM test1 WHERE MATCH('"document one"/1');SHOW META;
+------+----------+------------+----------+
| id   | group_id | date_added | weight() |
+------+----------+------------+----------+
|    1 |        1 | 1502280778 |     2663 |
|    2 |        1 | 1502280778 |     1528 |
+------+----------+------------+----------+
2 rows in set (0.00 sec)

+---------------+----------+
| Variable_name | Value    |
+---------------+----------+
| total         | 2        |
| total_found   | 2        |
| time          | 0.000    |
| keyword[0]    | document |
| docs[0]       | 2        |
| hits[0]       | 2        |
| keyword[1]    | one      |
| docs[1]       | 1        |
| hits[1]       | 2        |
+---------------+----------+
9 rows in set (0.00 sec)
mysql>  SET profiling=1;SELECT * FROM test1 WHERE id IN (1,2,4);SHOW PROFILE;
Query OK, 0 rows affected (0.00 sec)

+------+----------+------------+
| id   | group_id | date_added |
+------+----------+------------+
|    1 |        1 | 1502280778 |
|    2 |        1 | 1502280778 |
|    4 |        2 | 1502280778 |
+------+----------+------------+
3 rows in set (0.00 sec)

+--------------+----------+----------+---------+
| Status       | Duration | Switches | Percent |
+--------------+----------+----------+---------+
| unknown      | 0.000059 | 4        | 44.70   |
| net_read     | 0.000001 | 1        | 0.76    |
| local_search | 0.000042 | 1        | 31.82   |
| sql_parse    | 0.000012 | 1        | 9.09    |
| fullscan     | 0.000001 | 1        | 0.76    |
| finalize     | 0.000007 | 1        | 5.30    |
| aggregate    | 0.000006 | 2        | 4.55    |
| net_write    | 0.000004 | 1        | 3.03    |
| eval_post    | 0.000000 | 1        | 0.00    |
| total        | 0.000132 | 13       | 0       |
+--------------+----------+----------+---------+
10 rows in set (0.00 sec)
mysql> SELECT id, id%3 idd FROM test1 WHERE MATCH('this is | nothing') GROUP BY idd;SHOW PROFILE;
+------+------+
| id   | idd  |
+------+------+
|    1 |    1 |
|    2 |    2 |
|    3 |    0 |
+------+------+
3 rows in set (0.00 sec)

+--------+----------+----------+---------+
| Status | Duration | Switches | Percent |
+--------+----------+----------+---------+
| total  | 0.000000 | 0        | 0       |
+--------+----------+----------+---------+
1 row in set (0.00 sec)
mysql> SELECT id FROM test1 WHERE MATCH('is this a good plan?');SHOW PLAN\G
Empty set (0.00 sec)

*************************** 1. row ***************************
Variable: transformed_tree
        Value: AND(
        AND(KEYWORD(is, querypos=1)),
        AND(KEYWORD(this, querypos=2)),
        AND(KEYWORD(a, querypos=3)),
        AND(KEYWORD(good, querypos=4)),
        AND(KEYWORD(plan, querypos=5)))
1 row in set (0.00 sec)
mysql>  SELECT COUNT(*) c, id%3 idd FROM test1 GROUP BY idd HAVING COUNT(*)>1;
    +------+------+
    | c    | idd  |
    +------+------+
    |    2 |    1 |
    +------+------+
    1 row in set (0.00 sec)
mysql>  SELECT COUNT(*) FROM test1;
    +----------+
    | count(*) |
    +----------+
    |        4 |
    +----------+
    1 row in set (0.00 sec)
mysql>   CALL KEYWORDS ('one two three', 'test1', 1);
+------+-----------+------------+------+------+
| qpos | tokenized | normalized | docs | hits |
+------+-----------+------------+------+------+
| 1    | one       | one        | 1    | 2    |
| 2    | two       | two        | 1    | 2    |
| 3    | three     | three      | 0    | 0    |
+------+-----------+------------+------+------+
3 rows in set (0.00 sec)

Indexing

Data sources

The data to be indexed can generally come from very different sources: SQL databases, plain text files, HTML files, mailboxes, and so on. From Manticore point of view, the data it indexes is a set of structured documents, each of which has the same set of fields and attributes. This is similar to SQL, where each row would correspond to a document, and each column to either a field or an attribute.

Depending on what source Manticore should get the data from, different code is required to fetch the data and prepare it for indexing. This code is called data source driver (or simply driver or data source for brevity).

At the time of this writing, there are built-in drivers for MySQL, PostgreSQL, MS SQL (on Windows), and ODBC. There is also a generic driver called xmlpipe2, which runs a specified command and reads the data from its stdout. See xmlpipe2 data source section for the format description. tsvpipe (Tab Separated Values) and csvpipe (Comma Separated Values) data source also available and described in TSV/CSV data source.

There can be as many sources per index as necessary. They will be sequentially processed in the very same order which was specified in index definition. All the documents coming from those sources will be merged as if they were coming from a single source.

Full-text fields

Full-text fields (or just fields for brevity) are the textual document contents that get indexed by Manticore, and can be (quickly) searched for keywords.

Fields are named, and you can limit your searches to a single field (eg. search through “title” only) or a subset of fields (eg. to “title” and “abstract” only). Manticore index format generally supports up to 256 fields.

Note that the original contents of the fields are not stored in the Manticore index. The text that you send to Manticore gets processed, and a full-text index (a special data structure that enables quick searches for a keyword) gets built from that text. But the original text contents are then simply discarded. Manticore assumes that you store those contents elsewhere anyway.

Moreover, it is impossible to fully reconstruct the original text, because the specific whitespace, capitalization, punctuation, etc will all be lost during indexing. It is theoretically possible to partially reconstruct a given document from the Manticore full-text index, but that would be a slow process (especially if the CRC dictionary is used, which does not even store the original keywords and works with their hashes instead).

Attributes

Attributes are additional values associated with each document that can be used to perform additional filtering and sorting during search.

It is often desired to additionally process full-text search results based not only on matching document ID and its rank, but on a number of other per-document values as well. For instance, one might need to sort news search results by date and then relevance, or search through products within specified price range, or limit blog search to posts made by selected users, or group results by month. To do that efficiently, Manticore allows to attach a number of additional attributes to each document, and store their values in the full-text index. It’s then possible to use stored values to filter, sort, or group full-text matches.

Attributes, unlike the fields, are not full-text indexed. They are stored in the index, but it is not possible to search them as full-text, and attempting to do so results in an error.

For example, it is impossible to use the extended matching mode expression @column 1 to match documents where column is 1, if column is an attribute, and this is still true even if the numeric digits are normally indexed.

Attributes can be used for filtering, though, to restrict returned rows, as well as sorting or result grouping; it is entirely possible to sort results purely based on attributes, and ignore the search relevance tools. Additionally, attributes are returned from the search daemon, while the indexed text is not.

A good example for attributes would be a forum posts table. Assume that only title and content fields need to be full-text searchable - but that sometimes it is also required to limit search to a certain author or a sub-forum (ie. search only those rows that have some specific values of author_id or forum_id columns in the SQL table); or to sort matches by post_date column; or to group matching posts by month of the post_date and calculate per-group match counts.

This can be achieved by specifying all the mentioned columns (excluding title and content, that are full-text fields) as attributes, indexing them, and then using API calls to setup filtering, sorting, and grouping. Here as an example.

Example sphinx.conf part:

...
sql_query = SELECT id, title, content, \
    author_id, forum_id, post_date FROM my_forum_posts
sql_attr_uint = author_id
sql_attr_uint = forum_id
sql_attr_timestamp = post_date
...

Example application code (in PHP):

// only search posts by author whose ID is 123
$cl->SetFilter ( "author_id", array ( 123 ) );

// only search posts in sub-forums 1, 3 and 7
$cl->SetFilter ( "forum_id", array ( 1,3,7 ) );

// sort found posts by posting date in descending order
$cl->SetSortMode ( SPH_SORT_ATTR_DESC, "post_date" );

Attributes are named. Attribute names are case insensitive. Attributes are not full-text indexed; they are stored in the index as is. Currently supported attribute types are:

  • unsigned integers (1-bit to 32-bit wide);
  • signed big integers (64-bit wide);
  • UNIX timestamps;
  • floating point values (32-bit, IEEE 754 single precision);
  • strings;
  • JSON;
  • MVA, multi-value attributes (variable-length lists of 32-bit unsigned integers).

The complete set of per-document attribute values is sometimes referred to as docinfo. Docinfos can either be

  • stored separately from the main full-text index data (“extern” storage, in .spa file), or
  • attached to each occurrence of document ID in full-text index data (“inline” storage, in .spd file).

When using extern storage, a copy of .spa file (with all the attribute values for all the documents) is kept in RAM by searchd at all times. This is for performance reasons; random disk I/O would be too slow. On the contrary, inline storage does not require any additional RAM at all, but that comes at the cost of greatly inflating the index size: remember that it copies all attribute value every time when the document ID is mentioned, and that is exactly as many times as there are different keywords in the document. Inline may be the only viable option if you have only a few attributes and need to work with big datasets in limited RAM. However, in most cases extern storage makes both indexing and searching much more efficient.

Search-time memory requirements for extern storage are (1+number_of_attrs)*number_of_docs*4 bytes, ie. 10 million docs with 2 groups and 1 timestamp will take (1+2+1)*10M*4 = 160 MB of RAM. This is PER DAEMON, not per query. searchd will allocate 160 MB on startup, read the data and keep it shared between queries. The children will NOT allocate any additional copies of this data.

MVA (multi-valued attributes)

MVAs, or multi-valued attributes, are an important special type of per-document attributes in Manticore. MVAs let you attach sets of numeric values to every document. That is useful to implement article tags, product categories, etc. Filtering and group-by (but not sorting) on MVA attributes is supported.

MVA values can either be unsigned 32-bit integers (UNSIGNED INTEGER) or signed 64-bit integers (BIGINT).

The set size is not limited, you can have an arbitrary number of values attached to each document as long as RAM permits (.spm file that contains the MVA values will be precached in RAM by searchd). The source data can be taken either from a separate query, or from a document field; see source type in sql_attr_multi. In the first case the query will have to return pairs of document ID and MVA values, in the second one the field will be parsed for integer values. There are absolutely no requirements as to incoming data order; the values will be automatically grouped by document ID (and internally sorted within the same ID) during indexing anyway.

When filtering, a document will match the filter on MVA attribute if any of the values satisfy the filtering condition. (Therefore, documents that pass through exclude filters will not contain any of the forbidden values.) When grouping by MVA attribute, a document will contribute to as many groups as there are different MVA values associated with that document. For instance, if the collection contains exactly 1 document having a ‘tag’ MVA with values 5, 7, and 11, grouping on ‘tag’ will produce 3 groups with ‘COUNT(*)‘equal to 1 and ‘GROUPBY()’ key values of 5, 7, and 11 respectively. Also note that grouping by MVA might lead to duplicate documents in the result set: because each document can participate in many groups, it can be chosen as the best one in in more than one group, leading to duplicate IDs. PHP API historically uses ordered hash on the document ID for the resulting rows; so you’ll also need to use SetArrayResult() in order to employ group-by on MVA with PHP API.

Indexes

To be able to answer full-text search queries fast, Manticore needs to build a special data structure optimized for such queries from your text data. This structure is called index; and the process of building index from text is called indexing.

An index identifier must be a single word, that can contain letters, numbers and underscores. It must start with a letter.

Different index types are well suited for different tasks. For example, a disk-based tree-based index would be easy to update (ie. insert new documents to existing index), but rather slow to search. Manticore architecture allows internally for different index types, or backends, to be implemented comparatively easily.

Manticore provides 2 different backends: a disk index backend, and a RT (realtime) index backend.

Offline/plain indexes

Disk indexes are designed to provide maximum indexing and searching speed, while keeping the RAM footprint as low as possible. That comes at a cost of text index updates. You can not update an existing document or incrementally add a new document to a disk index. You only can batch rebuild the entire disk index from scratch. (Note that you still can update document’s attributes on the fly, even with the disk indexes.)

This “rebuild only” limitation might look as a big constraint at a first glance. But in reality, it can very frequently be worked around rather easily by setting up multiple disk indexes, searching through them all, and only rebuilding the one with a fraction of the most recently changed data. See Live index updates for details.

Real-Time indexes

RT indexes enable you to implement dynamic updates and incremental additions to the full text index. RT stands for Real Time and they are indeed “soft realtime” in terms of writes, meaning that most index changes become available for searching as quick as 1 millisecond or less, but could occasionally stall for seconds. (Searches will still work even during that occasional writing stall.) Refer to Real-time indexes for details.

Distributed indexes

Manticore supports so-called distributed indexes. Compared to disk and RT indexes, those are not a real physical backend, but rather just lists of either local or remote indexes that can be searched transparently to the application, with Manticore doing all the chores of sending search requests to remote machines in the cluster, aggregating the result sets, retrying the failed requests, and even doing some load balancing. See Distributed searching for a discussion of distributed indexes.

Templates indexes

Template indexes are indexes with no storage backend. They can be used operations that involve only data from input, like keywords and snippets generation.

Percolate indexes

Percolate indexes are special Real-Time indexes that store queries instead of documents. They are used for prospective searches ( or “search in reverse”). Refer to Percolate query for more details.

There can be as many indexes per configuration file as necessary. indexer utility can reindex either all of them (if --all option is specified), or a certain explicitly specified subset. searchd utility will serve all the specified indexes, and the clients can specify what indexes to search in run time.

Restrictions on the source data

There are a few different restrictions imposed on the source data which is going to be indexed by Manticore, of which the single most important one is:

ALL DOCUMENT IDS MUST BE UNIQUE UNSIGNED NON-ZERO INTEGER NUMBERS (32-BIT OR 64-BIT, DEPENDING ON BUILD TIME SETTINGS).

If this requirement is not met, different bad things can happen. For instance, Manticore can crash with an internal assertion while indexing; or produce strange results when searching due to conflicting IDs. Also, a 1000-pound gorilla might eventually come out of your display and start throwing barrels at you. You’ve been warned.

Charsets, case folding, translation tables, and replacement rules

When indexing some index, Manticore fetches documents from the specified sources, splits the text into words, and does case folding so that “Abc”, “ABC” and “abc” would be treated as the same word (or, to be pedantic, term).

To do that properly, Manticore needs to know

  • what encoding is the source text in (and this encoding should always be UTF-8);
  • what characters are letters and what are not;
  • what letters should be folded to what letters.

This should be configured on a per-index basis using charset_table. option. charset_table specifies the table that maps letter characters to their case folded versions. The characters that are not in the table are considered to be non-letters and will be treated as word separators when indexing or searching through this index.

Default tables currently include English and Russian characters. Please do submit your tables for other languages!

You can also specify text pattern replacement rules. For example, given the rules

regexp_filter = \**(\d+)\" => \1 inch
regexp_filter = (BLUE|RED) => COLOR

the text ‘RED TUBE 5” LONG’ would be indexed as ‘COLOR TUBE 5 INCH LONG’, and ‘PLANK 2” x 4“‘as ‘PLANK 2 INCH x 4 INCH’. Rules are applied in the given order. Text in queries is also replaced; a search for”BLUE TUBE” would actually become a search for “COLOR TUBE”. Note that Manticore must be built with the –with-re2 option to use this feature.

SQL data sources (MySQL, PostgreSQL)

With all the SQL drivers, indexing generally works as follows.

  • connection to the database is established;
  • pre-query (see sql_query_pre) is executed to perform any necessary initial setup, such as setting per-connection encoding with MySQL;
  • main query (see sql_query) is executed and the rows it returns are indexed;
  • post-query (see sql_query_post) is executed to perform any necessary cleanup;
  • connection to the database is closed;
  • indexer does the sorting phase (to be pedantic, index-type specific post-processing);
  • connection to the database is established again;
  • post-index query (see sql_query_post_index) is executed to perform any necessary final cleanup;
  • connection to the database is closed again.

Most options, such as database user/host/password, are straightforward. However, there are a few subtle things, which are discussed in more detail here.

Ranged queries

Main query, which needs to fetch all the documents, can impose a read lock on the whole table and stall the concurrent queries (eg. INSERTs to MyISAM table), waste a lot of memory for result set, etc. To avoid this, Manticore supports so-called ranged queries. With ranged queries, Manticore first fetches min and max document IDs from the table, and then substitutes different ID intervals into main query text and runs the modified query to fetch another chunk of documents. Here’s an example.

Example 3.1. Ranged query usage example

# in sphinx.conf

sql_query_range = SELECT MIN(id),MAX(id) FROM documents
sql_range_step = 1000
sql_query = SELECT * FROM documents WHERE id>=$start AND id<=$end

If the table contains document IDs from 1 to, say, 2345, then sql_query would be run three times:

  1. with $start replaced with 1 and $end replaced with 1000;
  2. with $start replaced with 1001 and $end replaced with 2000;
  3. with $start replaced with 2001 and $end replaced with 2345.

Obviously, that’s not much of a difference for 2000-row table, but when it comes to indexing 10-million-row MyISAM table, ranged queries might be of some help.

sql_query_post vs. sql_query_post_index

The difference between post-query and post-index query is in that post-query is run immediately when Manticore received all the documents, but further indexing may still fail for some other reason. On the contrary, by the time the post-index query gets executed, it is guaranteed that the indexing was successful. Database connection is dropped and re-established because sorting phase can be very lengthy and would just timeout otherwise.

xmlpipe2 data source

xmlpipe2 lets you pass arbitrary full-text and attribute data to Manticore in yet another custom XML format. It also allows to specify the schema (ie. the set of fields and attributes) either in the XML stream itself, or in the source settings.

When indexing xmlpipe2 source, indexer runs the given command, opens a pipe to its stdout, and expects well-formed XML stream. Here’s sample stream data:

Example 3.2. xmlpipe2 document stream

<?xml version="1.0" encoding="utf-8"?>
<sphinx:docset>

<sphinx:schema>
<sphinx:field name="subject"/>
<sphinx:field name="content"/>
<sphinx:attr name="published" type="timestamp"/>
<sphinx:attr name="author_id" type="int" bits="16" default="1"/>
</sphinx:schema>

<sphinx:document id="1234">
<content>this is the main content <![CDATA[[and this <cdata> entry
must be handled properly by xml parser lib]]></content>
<published>1012325463</published>
<subject>note how field/attr tags can be
in <** class="red">randomized** order</subject>
<misc>some undeclared element</misc>
</sphinx:document>

<sphinx:document id="1235">
<subject>another subject</subject>
<content>here comes another document, and i am given to understand,
that in-document field order must not matter, sir</content>
<published>1012325467</published>
</sphinx:document>

<!-- ... even more sphinx:document entries here ... -->

<sphinx:killlist>
<id>1234</id>
<id>4567</id>
</sphinx:killlist>

</sphinx:docset>

Arbitrary fields and attributes are allowed. They also can occur in the stream in arbitrary order within each document; the order is ignored. There is a restriction on maximum field length; fields longer than 2 MB will be truncated to 2 MB (this limit can be changed in the source).

The schema, ie. complete fields and attributes list, must be declared before any document could be parsed. This can be done either in the configuration file using xmlpipe_field and xmlpipe_attr_XXX settings, or right in the stream using <sphinx:schema> element. <sphinx:schema> is optional. It is only allowed to occur as the very first sub-element in <sphinx:docset>. If there is no in-stream schema definition, settings from the configuration file will be used. Otherwise, stream settings take precedence.

Unknown tags (which were not declared neither as fields nor as attributes) will be ignored with a warning. In the example above, <misc> will be ignored. All embedded tags and their attributes (such as ** in <subject> in the example above) will be silently ignored.

Support for incoming stream encodings depends on whether iconv is installed on the system. xmlpipe2 is parsed using libexpat parser that understands US-ASCII, ISO-8859-1, UTF-8 and a few UTF-16 variants natively. Manticore configure script will also check for libiconv presence, and utilize it to handle other encodings. libexpat also enforces the requirement to use UTF-8 charset on Manticore side, because the parsed data it returns is always in UTF-8.

XML elements (tags) recognized by xmlpipe2 (and their attributes where applicable) are:

  • sphinx:docset
  • Mandatory top-level element, denotes and contains xmlpipe2 document set.
  • sphinx:schema
  • Optional element, must either occur as the very first child of sphinx:docset, or never occur at all. Declares the document schema. Contains field and attribute declarations. If present, overrides per-source settings from the configuration file.
  • sphinx:field
  • Optional element, child of sphinx:schema. Declares a full-text field. Known attributes are:
    • “name”, specifies the XML element name that will be treated as a full-text field in the subsequent documents.
    • “attr”, specifies whether to also index this field as a string. Possible value is “string”.
  • sphinx:attr
  • Optional element, child of sphinx:schema. Declares an attribute. Known attributes are:
    • “name”, specifies the element name that should be treated as an attribute in the subsequent documents.
    • “type”, specifies the attribute type. Possible values are “int”, “bigint”, “timestamp”, “bool”, “float”, “multi” and “json”.
    • “bits”, specifies the bit size for “int” attribute type. Valid values are 1 to 32.
    • “default”, specifies the default value for this attribute that should be used if the attribute’s element is not present in the document.
  • sphinx:document
  • Mandatory element, must be a child of sphinx:docset. Contains arbitrary other elements with field and attribute values to be indexed, as declared either using sphinx:field and sphinx:attr elements or in the configuration file. The only known attribute is “id” that must contain the unique integer document ID.
  • sphinx:killlist
  • Optional element, child of sphinx:docset. Contains a number of “id” elements whose contents are document IDs to be put into a kill-list for this index.

TSV/CSV data source

This is the simplest way to pass data to the indexer. It was created due to xmlpipe2 limitations. Namely, indexer must map each attribute and field tag in XML file to corresponding schema element. This mapping requires some time. And time increases with increasing the number of fields and attributes in schema. There is no such issue in tsvpipe because each field and attribute is a particular column in TSV file. So, in some cases tsvpipe could work slightly faster than xmlpipe2.

The first column in TSVCSV file must be a document ID. The rest ones must mirror the declaration of fields and attributes in schema definition.

The difference between tsvpipe and csvpipe is delimiter and quoting rules. tsvpipe has tab character as hardcoded delimiter and has no quoting rules. csvpipe has option csvpipe_delimiter for delimiter with default value ‘,’ and also has quoting rules, such as:

  • any field may be quoted
  • fields containing a line-break, double-quote or commas should be quoted
  • a double quote character in a field must be represented by two double quote characters

tsvpipe and csvpipe have same field and attrribute declaration derectives as xmlpipe.

tsvpipe declarations:

tsvpipe_command, tsvpipe_field, tsvpipe_field_string, tsvpipe_attr_uint, tsvpipe_attr_timestamp, tsvpipe_attr_bool, tsvpipe_attr_float, tsvpipe_attr_bigint, tsvpipe_attr_multi, tsvpipe_attr_multi_64, tsvpipe_attr_string, tsvpipe_attr_json

csvpipe declarations:

csvpipe_command, csvpipe_field, csvpipe_field_string, csvpipe_attr_uint, csvpipe_attr_timestamp, csvpipe_attr_bool, csvpipe_attr_float, csvpipe_attr_bigint, csvpipe_attr_multi, csvpipe_attr_multi_64, csvpipe_attr_string, csvpipe_attr_json

source tsv_test
{
    type = tsvpipe
    tsvpipe_command = cat /tmp/rock_bands.tsv
    tsvpipe_field = name
    tsvpipe_attr_multi = genre_tags
}
1   Led Zeppelin    35,23,16
2   Deep Purple 35,92
3   Frank Zappa 35,23,16,92,33,24

Live index updates

There are two major approaches to maintaining the full-text index contents up to date. Note, however, that both these approaches deal with the task of full-text data updates, and not attribute updates (which are already supported, refer to UpdateAttributes API call description for details.)

First, you can use disk-based indexes, partition them manually, and only rebuild the smaller partitions (so-called “deltas”) frequently. By minimizing the rebuild size, you can reduce the average indexing lag to something as low as 30-60 seconds. On huge collections it actually might be the most efficient one. Refer to Delta index updates for details.

Second, using real-time indexes (RT indexes for short) that on-the-fly updates of the full-text data. Updates on a RT index can appear in the search results in 1-2 milliseconds, ie. 0.001-0.002 seconds. However, RT index are less efficient for bulk indexing huge amounts of data. Refer to Real-time indexes for details.

Delta index updates

There’s a frequent situation when the total dataset is too big to be reindexed from scratch often, but the amount of new records is rather small. Example: a forum with a 1,000,000 archived posts, but only 1,000 new posts per day.

In this case, “live” (almost real time) index updates could be implemented using so called “main+delta” scheme.

The idea is to set up two sources and two indexes, with one “main” index for the data which only changes rarely (if ever), and one “delta” for the new documents. In the example above, 1,000,000 archived posts would go to the main index, and newly inserted 1,000 posts/day would go to the delta index. Delta index could then be reindexed very frequently, and the documents can be made available to search in a matter of minutes.

Specifying which documents should go to what index and reindexing main index could also be made fully automatic. One option would be to make a counter table which would track the ID which would split the documents, and update it whenever the main index is reindexed.

Example 3.3. Fully automated live updates

# in MySQL
CREATE TABLE sph_counter
(
    counter_id INTEGER PRIMARY KEY NOT NULL,
    max_doc_id INTEGER NOT NULL
);

# in sphinx.conf
source main
{
    # ...
    sql_query_pre = SET NAMES utf8
    sql_query_pre = REPLACE INTO sph_counter SELECT 1, MAX(id) FROM documents
    sql_query = SELECT id, title, body FROM documents \
        WHERE id<=( SELECT max_doc_id FROM sph_counter WHERE counter_id=1 )
}

source delta : main
{
    sql_query_pre = SET NAMES utf8
    sql_query = SELECT id, title, body FROM documents \
        WHERE id>( SELECT max_doc_id FROM sph_counter WHERE counter_id=1 )
}

index main
{
    source = main
    path = /path/to/main
    # ... all the other settings
}

# note how all other settings are copied from main,
# but source and path are overridden (they MUST be)
index delta : main
{
    source = delta
    path = /path/to/delta
}

Note how we’re overriding sql_query_pre in the delta source. We need to explicitly have that override. Otherwise REPLACE query would be run when indexing delta source too, effectively nullifying it. However, when we issue the directive in the inherited source for the first time, it removes all inherited values, so the encoding setup is also lost. So sql_query_pre in the delta can not just be empty; and we need to issue the encoding setup query explicitly once again.

Index merging

Merging two existing indexes can be more efficient than indexing the data from scratch, and desired in some cases (such as merging ‘main’ and ‘delta’ indexes instead of simply reindexing ‘main’ in ‘main+delta’ partitioning scheme). So indexer has an option to do that. Merging the indexes is normally faster than reindexing but still not instant on huge indexes. Basically, it will need to read the contents of both indexes once and write the result once. Merging 100 GB and 1 GB index, for example, will result in 202 GB of IO (but that’s still likely less than the indexing from scratch requires).

The basic command syntax is as follows:

indexer --merge DSTINDEX SRCINDEX [--rotate]

Only the DSTINDEX index will be affected: the contents of SRCINDEX will be merged into it. --rotate switch will be required if DSTINDEX is already being served by searchd. The initially devised usage pattern is to merge a smaller update from SRCINDEX into DSTINDEX. Thus, when merging the attributes, values from SRCINDEX will win if duplicate document IDs are encountered. Note, however, that the “old” keywords will not be automatically removed in such cases. For example, if there’s a keyword “old” associated with document 123 in DSTINDEX, and a keyword “new” associated with it in SRCINDEX, document 123 will be found by both keywords after the merge. You can supply an explicit condition to remove documents from DSTINDEX to mitigate that; the relevant switch is --merge-dst-range:

indexer --merge main delta --merge-dst-range deleted 0 0

This switch lets you apply filters to the destination index along with merging. There can be several filters; all of their conditions must be met in order to include the document in the resulting merged index. In the example above, the filter passes only those records where ‘deleted’ is 0, eliminating all records that were flagged as deleted (for instance, using UpdateAttributes() call).

Real-time indexes

Real-time indexes (or RT indexes for brevity) are a backend that lets you insert, update, or delete documents (rows) on the fly. While querying of RT indexes is possible using any of the SphinxAPI, SphinxQL, or SphinxSE, updating them is only possible via SphinxQL at the moment. Full SphinxQL reference is available in SphinxQL reference.

RT indexes overview

RT indexes should be declared in sphinx.conf, just as every other index type. Notable differences from the regular, disk-based indexes are that a) data sources are not required and ignored, and b) you should explicitly enumerate all the text fields, not just attributes. Here’s an example:

Example 4.1. RT index declaration

index rt
{
    type = rt
    path = /usr/local/sphinx/data/rt
    rt_field = title
    rt_field = content
    rt_attr_uint = gid
}

RT index can be accessed using MySQL protocol. INSERT, REPLACE, DELETE, and SELECT statements against RT index are supported. For instance, this is an example session with the sample index above:

$ mysql -h 127.0.0.1 -P 9306
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 1.10-dev (r2153)

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql> INSERT INTO rt VALUES ( 1, 'first record', 'test one', 123 );
Query OK, 1 row affected (0.05 sec)

mysql> INSERT INTO rt VALUES ( 2, 'second record', 'test two', 234 );
Query OK, 1 row affected (0.00 sec)

mysql> SELECT * FROM rt;
+------+--------+------+
| id   | weight | gid  |
+------+--------+------+
|    1 |      1 |  123 |
|    2 |      1 |  234 |
+------+--------+------+
2 rows in set (0.02 sec)

mysql> SELECT * FROM rt WHERE MATCH('test');
+------+--------+------+
| id   | weight | gid  |
+------+--------+------+
|    1 |   1643 |  123 |
|    2 |   1643 |  234 |
+------+--------+------+
2 rows in set (0.01 sec)

mysql> SELECT * FROM rt WHERE MATCH('@title test');
Empty set (0.00 sec)

Both partial and batch INSERT syntaxes are supported, ie. you can specify a subset of columns, and insert several rows at a time. Deletions are also possible using DELETE statement; the only currently supported syntax is DELETE FROM <index> WHERE id=<id>. REPLACE is also supported, enabling you to implement updates.

mysql> INSERT INTO rt ( id, title ) VALUES ( 3, 'third row' ), ( 4, 'fourth entry' );
Query OK, 2 rows affected (0.01 sec)

mysql> SELECT * FROM rt;
+------+--------+------+
| id   | weight | gid  |
+------+--------+------+
|    1 |      1 |  123 |
|    2 |      1 |  234 |
|    3 |      1 |    0 |
|    4 |      1 |    0 |
+------+--------+------+
4 rows in set (0.00 sec)

mysql> DELETE FROM rt WHERE id=2;
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT * FROM rt WHERE MATCH('test');
+------+--------+------+
| id   | weight | gid  |
+------+--------+------+
|    1 |   1500 |  123 |
+------+--------+------+
1 row in set (0.00 sec)

mysql> INSERT INTO rt VALUES ( 1, 'first record on steroids', 'test one', 123 );
ERROR 1064 (42000): duplicate id '1'

mysql> REPLACE INTO rt VALUES ( 1, 'first record on steroids', 'test one', 123 );
Query OK, 1 row affected (0.01 sec)

mysql> SELECT * FROM rt WHERE MATCH('steroids');
+------+--------+------+
| id   | weight | gid  |
+------+--------+------+
|    1 |   1500 |  123 |
+------+--------+------+
1 row in set (0.01 sec)

Data stored in RT index should survive clean shutdown. When binary logging is enabled, it should also survive crash and/or dirty shutdown, and recover on subsequent startup.

Known caveats with RT indexes

RT indexes are currently quality feature, but there are still a few known usage quirks. Those quirks are listed in this section.

  • Default conservative RAM chunk limit (rt_mem_limit) of 32M can lead to poor performance on bigger indexes, you should raise it to 256..1024M if you’re planning to index gigabytes.
  • The only attribute storage mode is ‘extern’ which requires at least one attribute to be present.
  • High DELETE/REPLACE rate can lead to kill-list fragmentation and impact searching performance.
  • No transaction size limits are currently imposed; too many concurrent INSERT/REPLACE transactions might therefore consume a lot of RAM.
  • In case of a damaged binlog, recovery will stop on the first damaged transaction, even though it’s technically possible to keep looking further for subsequent undamaged transactions, and recover those. This mid-file damage case (due to flaky HDD/CDD/tape?) is supposed to be extremely rare, though.
  • Multiple INSERTs grouped in a single transaction perform better than equivalent single-row transactions and are recommended for batch loading of data.

RT index internals

RT index is internally chunked. It keeps a so-called RAM chunk that stores all the most recent changes. RAM chunk memory usage is rather strictly limited with per-index rt_mem_limit directive. Once RAM chunk grows over this limit, a new disk chunk is created from its data, and RAM chunk is reset. Thus, while most changes on the RT index will be performed in RAM only and complete instantly (in milliseconds), those changes that overflow the RAM chunk will stall for the duration of disk chunk creation (a few seconds).

Manticore uses double-buffering to avoid INSERT stalls. When data is being dumped to disk, the second buffer is used, so further INSERTs won’t be delayed. The second buffer is defined to be 10% the size of the standard buffer, rt_mem_limit, but future versions of Manticore may allow configuring this further.

Disk chunks are, in fact, just regular disk-based indexes. But they’re a part of an RT index and automatically managed by it, so you need not configure nor manage them manually. Because a new disk chunk is created every time RT chunk overflows the limit, and because in-memory chunk format is close to on-disk format, the disk chunks will be approximately rt_mem_limit bytes in size each.

Generally, it is better to set the limit bigger, to minimize both the frequency of flushes, and the index fragmentation (number of disk chunks). For instance, on a dedicated search server that handles a big RT index, it can be advised to set rt_mem_limit to 1-2 GB. A global limit on all indexes is also planned, but not yet implemented.

Disk chunk full-text index data can not be actually modified, so the full-text field changes (ie. row deletions and updates) suppress a previous row version from a disk chunk using a kill-list, but do not actually physically purge the data. Therefore, on workloads with high full-text updates ratio index might eventually get polluted by these previous row versions, and searching performance would degrade. Physical index purging that would improve the performance may be performed with OPTIMIZE command.

Data in RAM chunk gets saved to disk on clean daemon shutdown, and then loaded back on startup. However, on daemon or server crash, updates from RAM chunk might be lost. To prevent that, binary logging of transactions can be used; see the section called :ref:`binary_logging for details.

Full-text changes in RT index are transactional. They are stored in a per-thread accumulator until COMMIT, then applied at once. Bigger batches per single COMMIT should result in faster indexing.

Binary logging

Binary logs are essentially a recovery mechanism. With binary logs enabled, searchd writes every given transaction to the binlog file, and uses that for recovery after an unclean shutdown. On clean shutdown, RAM chunks are saved to disk, and then all the binlog files are unlinked.

During normal operation, a new binlog file will be opened every time when binlog_max_log_size limit is reached. Older, already closed binlog files are kept until all of the transactions stored in them (from all indexes) are flushed as a disk chunk. Setting the limit to 0 pretty much prevents binlog from being unlinked at all while searchd is running; however, it will still be unlinked on clean shutdown. (binlog_max_log_size defaults to 0.)

There are 3 different binlog flushing strategies, controlled by binlog_flush directive which takes the values of 0, 1, or 2. 0 means to flush the log to OS and sync it to disk every second; 1 means flush and sync every transaction; and 2 (the default mode) means flush every transaction but sync every second. Sync is relatively slow because it has to perform physical disk writes, so mode 1 is the safest (every committed transaction is guaranteed to be written on disk) but the slowest. Flushing log to OS prevents from data loss on searchd crashes but not system crashes. Mode 2 is the default.

On recovery after an unclean shutdown, binlogs are replayed and all logged transactions since the last good on-disk state are restored. Transactions are checksummed so in case of binlog file corruption garbage data will not be replayed; such a broken transaction will be detected and, currently, will stop replay. Transactions also start with a magic marker and timestamped, so in case of binlog damage in the middle of the file, it’s technically possible to skip broken transactions and keep replaying from the next good one, and/or it’s possible to replay transactions until a given timestamp (point-in-time recovery), but none of that is implemented yet.

One unwanted side effect of binlogs is that actively updating a small RT index that fully fits into a RAM chunk part will lead to an ever-growing binlog that can never be unlinked until clean shutdown. Binlogs are essentially append-only deltas against the last known good saved state on disk, and unless RAM chunk gets saved, they can not be unlinked. An ever-growing binlog is not very good for disk use and crash recovery time. To avoid this, you can configure searchd to perform a periodic RAM chunk flush to fix that problem using a rt_flush_period directive. With periodic flushes enabled, searchd will keep a separate thread, checking whether RT indexes RAM chunks need to be written back to disk. Once that happens, the respective binlogs can be (and are) safely unlinked.

Note that rt_flush_period only controls the frequency at which the checks happen. There are no guarantees that the particular RAM chunk will get saved. For instance, it does not make sense to regularly re-save a huge RAM chunk that only gets a few rows worth of updates. The search daemon determine whether to actually perform the flush with a few heuristics.

Searching

Matching modes

So-called matching modes are a legacy feature that used to provide (very) limited query syntax and ranking support. Currently, they are deprecated in favor of full-text query language and so-called Available built-in rankers. It is thus strongly recommended to use SPH_MATCH_EXTENDED and proper query syntax rather than any other legacy mode. All those other modes are actually internally converted to extended syntax anyway. SphinxAPI still defaults to SPH_MATCH_ALL but that is for compatibility reasons only.

There are the following matching modes available:

  • SPH_MATCH_ALL, matches all query words;
  • SPH_MATCH_ANY, matches any of the query words;
  • SPH_MATCH_PHRASE, matches query as a phrase, requiring perfect match;
  • SPH_MATCH_BOOLEAN, matches query as a boolean expression (see Boolean query syntax);
  • SPH_MATCH_EXTENDED, matches query as an expression in Manticore internal query language (see Extended query syntax);
  • SPH_MATCH_EXTENDED2, an alias for SPH_MATCH_EXTENDED (default mode);
  • SPH_MATCH_FULLSCAN, matches query, forcibly using the “full scan” mode as below. NB, any query terms will be ignored, such that filters, filter-ranges and grouping will still be applied, but no text-matching.

The SPH_MATCH_FULLSCAN mode will be automatically activated in place of the specified matching mode when the following conditions are met:

  1. The query string is empty (ie. its length is zero).
  2. docinfo storage is set to extern.

In full scan mode, all the indexed documents will be considered as matching. Such queries will still apply filters, sorting, and group by, but will not perform any full-text searching. This can be useful to unify full-text and non-full-text searching code, or to offload SQL server (there are cases when Manticore scans will perform better than analogous MySQL queries). An example of using the full scan mode might be to find posts in a forum. By selecting the forum’s user ID via SetFilter() but not actually providing any search text, Manticore will match every document (i.e. every post) where SetFilter() would match - in this case providing every post from that user. By default this will be ordered by relevancy, followed by Manticore document ID in ascending order (earliest first).

Boolean query syntax

Boolean queries allow the following special operators to be used:

  • operator OR:
hello | world
  • operator NOT:
hello -world
hello !world
  • grouping:
( hello world )

Here’s an example query which uses all these operators:

Example 5.1. Boolean query example

( cat -dog ) | ( cat -mouse)

There always is implicit AND operator, so “hello world” query actually means “hello & world”.

OR operator precedence is higher than AND, so “looking for cat | dog | mouse” means “looking for ( cat | dog | mouse )” and not “(looking for cat) | dog | mouse”.

Queries may be automatically optimized if OPTION boolean_simplify=1 is specified. Some transformations performed by this optimization include:

  • Excess brackets: ((A | B) | C) becomes ( A | B | C ); ((A B) C) becomes ( A B C )
  • Excess AND NOT: ((A !N1) !N2) becomes (A !(N1 | N2))
  • Common NOT: ((A !N) | (B !N)) becomes ((A|B) !N)
  • Common Compound NOT: ((A !(N AA)) | (B !(N BB))) becomes (((A|B) !N) | (A !AA) | (B !BB)) if the cost of evaluating N is greater than the added together costs of evaluating A and B
  • Common subterm: ((A (N | AA)) | (B (N | BB))) becomes (((A|B) N) | (A AA) | (B BB)) if the cost of evaluating N is greater than the added together costs of evaluating A and B
  • Common keywords: (A | “A B”~N) becomes A; (“A B” | “A B C”) becomes “A B”; (“A B”~N | “A B C”~N) becomes (“A B”~N)
  • Common phrase: (“X A B” | “Y A B”) becomes ((“X|Y”) “A B”)
  • Common AND NOT: ((A !X) | (A !Y) | (A !Z)) becomes (A !(X Y Z))
  • Common OR NOT: ((A !(N | N1)) | (B !(N | N2))) becomes (( (A !N1) | (B !N2) ) !N)

Note that optimizing the queries consumes CPU time, so for simple queries -or for hand-optimized queries- you’ll do better with the default boolean_simplify=0 value. Simplifications are often better for complex queries, or algorithmically generated queries.

Queries like “-dog”, which implicitly include all documents from the collection, can not be evaluated. This is both for technical and performance reasons. Technically, Manticore does not always keep a list of all IDs. Performance-wise, when the collection is huge (ie. 10-100M documents), evaluating such queries could take very long.

Extended query syntax

The following special operators and modifiers can be used when using the extended matching mode:

  • operator OR:
hello | world
  • operator MAYBE:
hello MAYBE world
  • operator NOT:
hello -world
hello !world
  • field search operator:
@title hello @body world
  • field position limit modifier:
@body[50] hello
  • multiple-field search operator:
@(title,body) hello world
  • ignore field search operator (will ignore any matches of ‘hello world’ from field ‘title’):
@!title hello world
  • ignore multiple-field search operator (if we have fields title, subject and body then @!(title) is equivalent to @(subject,body)):
@!(title,body) hello world
  • all-field search operator:
@* hello
  • phrase search operator:
"hello world"
  • proximity search operator:
"hello world"~10
  • quorum matching operator:
"the world is a wonderful place"/3
  • strict order operator (aka operator “before”):
aaa << bbb << ccc
  • exact form modifier:
raining =cats and =dogs
  • field-start and field-end modifier:
^hello world$
  • keyword IDF boost modifier:
boosted^1.234 boostedfieldend$^1.234
  • NEAR, generalized proximity operator:
hello NEAR/3 world NEAR/4 "my test"
  • SENTENCE operator:
all SENTENCE words SENTENCE "in one sentence"
  • PARAGRAPH operator:
"Bill Gates" PARAGRAPH "Steve Jobs"
  • ZONE limit operator:
    ZONE:(h3,h4)

only in these titles
  • ZONESPAN limit operator:
    ZONESPAN:(h2)

only in a (single) title

Here’s an example query that uses some of these operators:

Example 5.2. Extended matching mode: query example

"hello world" @title "example program"~5 @body python -(php|perl) @* code

The full meaning of this search is:

  • Find the words ‘hello’ and ‘world’ adjacently in any field in a document;
  • Additionally, the same document must also contain the words ‘example’ and ‘program’ in the title field, with up to, but not including, 5 words between the words in question; (E.g. “example PHP program” would be matched however “example script to introduce outside data into the correct context for your program” would not because two terms have 5 or more words between them)
  • Additionally, the same document must contain the word ‘python’ in the body field, but not contain either ‘php’ or ‘perl’;
  • Additionally, the same document must contain the word ‘code’ in any field.

There always is implicit AND operator, so “hello world” means that both “hello” and “world” must be present in matching document.

OR operator precedence is higher than AND, so “looking for cat | dog | mouse” means “looking for ( cat | dog | mouse )” and not “(looking for cat) | dog | mouse”.

Field limit operator limits subsequent searching to a given field. Normally, query will fail with an error message if given field name does not exist in the searched index. However, that can be suppressed by specifying “@@relaxed” option at the very beginning of the query:

@@relaxed @nosuchfield my query

This can be helpful when searching through heterogeneous indexes with different schemas.

Field position limit additionally restricts the searching to first N position within given field (or fields). For example, “@body [50] hello” will not match the documents where the keyword ‘hello’ occurs at position 51 and below in the body.

Proximity distance is specified in words, adjusted for word count, and applies to all words within quotes. For instance, “cat dog mouse”~5 query means that there must be less than 8-word span which contains all 3 words, ie. “CAT aaa bbb ccc DOG eee fff MOUSE” document will not match this query, because this span is exactly 8 words long.

Quorum matching operator introduces a kind of fuzzy matching. It will only match those documents that pass a given threshold of given words. The example above (“the world is a wonderful place”/3) will match all documents that have at least 3 of the 6 specified words. Operator is limited to 255 keywords. Instead of an absolute number, you can also specify a number between 0.0 and 1.0 (standing for 0% and 100%), and Manticore will match only documents with at least the specified percentage of given words. The same example above could also have been written “the world is a wonderful place”/0.5 and it would match documents with at least 50% of the 6 words.

Strict order operator (aka operator “before”) will match the document only if its argument keywords occur in the document exactly in the query order. For instance, “black << cat” query (without quotes) will match the document “black and white cat” but not the “that cat was black” document. Order operator has the lowest priority. It can be applied both to just keywords and more complex expressions, ie. this is a valid query:

(bag of words) << "exact phrase" << red|green|blue

Exact form keyword modifier will match the document only if the keyword occurred in exactly the specified form. The default behavior is to match the document if the stemmed keyword matches. For instance, “runs” query will match both the document that contains “runs” and the document that contains “running”, because both forms stem to just “run” - while “=runs” query will only match the first document. Exact form operator requires index_exact_words option to be enabled. This is a modifier that affects the keyword and thus can be used within operators such as phrase, proximity, and quorum operators. It is possible to apply an exact form modifier to the phrase operator. It’s really just syntax sugar - it adds an exact form modifier to all terms contained within the phrase.

="exact phrase"

Field-start and field-end keyword modifiers will make the keyword match only if it occurred at the very start or the very end of a fulltext field, respectively. For instance, the query “^hello world$” (with quotes and thus combining phrase operator and start/end modifiers) will only match documents that contain at least one field that has exactly these two keywords.

Arbitrarily nested brackets and negations are allowed. However, the query must be possible to compute without involving an implicit list of all documents:

// correct query
aaa -(bbb -(ccc ddd))

// queries that are non-computable
-aaa
aaa | -bbb

The phrase search operator may include a ‘match any term’ modifier. Terms within the phrase operator are position significant. When the ‘match any term’ modifier is implemented, the position of the subsequent terms from that phrase query will be shifted. Therefore, ‘match any’ has no impact on search performance.

"exact * phrase * * for terms"

NEAR operator is a generalized version of a proximity operator. The syntax is NEAR/N, it is case-sensitive, and no spaces are allowed between the NEAR keyword, the slash sign, and the distance value.

The original proximity operator only worked on sets of keywords. NEAR is more generic and can accept arbitrary subexpressions as its two arguments, matching the document when both subexpressions are found within N words of each other, no matter in which order. NEAR is left associative and has the same (lowest) precedence as BEFORE.

You should also note how a (one NEAR/7 two NEAR/7 three) query using NEAR is not really equivalent to a ("one two three"~7) one using keyword proximity operator. The difference here is that the proximity operator allows for up to 6 non-matching words between all the 3 matching words, but the version with NEAR is less restrictive: it would allow for up to 6 words between ‘one’ and ‘two’ and then for up to 6 more between that two-word matching and a ‘three’ keyword.

SENTENCE and PARAGRAPH operators matches the document when both its arguments are within the same sentence or the same paragraph of text, respectively. The arguments can be either keywords, or phrases, or the instances of the same operator. Here are a few examples:

one SENTENCE two
one SENTENCE "two three"
one SENTENCE "two three" SENTENCE four

The order of the arguments within the sentence or paragraph does not matter. These operators only work on indexes built with index_sp (sentence and paragraph indexing feature) enabled, and revert to a mere AND otherwise. Refer to the index_sp directive documentation for the notes on what’s considered a sentence and a paragraph.

ZONE limit operator is quite similar to field limit operator, but restricts matching to a given in-field zone or a list of zones. Note that the subsequent subexpressions are not required to match in a single contiguous span of a given zone, and may match in multiple spans. For instance, (ZONE:th hello world) query will match this example document:

<th>Table 1\. Local awareness of Hello Kitty brand.</th>
.. some table data goes here ..
<th>Table 2\. World-wide brand awareness.</th>

ZONE operator affects the query until the next field or ZONE limit operator, or the closing parenthesis. It only works on the indexes built with zones support (see index_zones) and will be ignored otherwise.

ZONESPAN limit operator is similar to the ZONE operator, but requires the match to occur in a single contiguous span. In the example above, (ZONESPAN:th hello world) would not match the document, since “hello” and “world” do not occur within the same span.

MAYBE operator works much like | operator but doesn’t return documents which match only right subtree expression.

Search results ranking

Ranking overview

Ranking (aka weighting) of the search results can be defined as a process of computing a so-called relevance (aka weight) for every given matched document with regards to a given query that matched it. So relevance is in the end just a number attached to every document that estimates how relevant the document is to the query. Search results can then be sorted based on this number and/or some additional parameters, so that the most sought after results would come up higher on the results page.

There is no single standard one-size-fits-all way to rank any document in any scenario. Moreover, there can not ever be such a way, because relevance is subjective. As in, what seems relevant to you might not seem relevant to me. Hence, in general case it’s not just hard to compute, it’s theoretically impossible.

So ranking in Manticore is configurable. It has a notion of a so-called ranker. A ranker can formally be defined as a function that takes document and query as its input and produces a relevance value as output. In layman’s terms, a ranker controls exactly how (using which specific algorithm) will Manticore assign weights to the document.

Previously, this ranking function was rigidly bound to the matching mode. So in the legacy matching modes (that is, SPH_MATCH_ALL, SPH_MATCH_ANY, SPH_MATCH_PHRASE, and SPH_MATCH_BOOLEAN) you can not choose the ranker. You can only do that in the SPH_MATCH_EXTENDED mode. (Which is the only mode in SphinxQL and the suggested mode in SphinxAPI anyway.) To choose a non-default ranker you can either use SetRankingMode() with SphinxAPI, or OPTION ranker clause in SELECT statement when using SphinxQL.

As a sidenote, legacy matching modes are internally implemented via the unified syntax anyway. When you use one of those modes, Manticore just internally adjusts the query and sets the associated ranker, then executes the query using the very same unified code path.

Available built-in rankers

Manticore ships with a number of built-in rankers suited for different purposes. A number of them uses two factors, phrase proximity (aka LCS) and BM25. Phrase proximity works on the keyword positions, while BM25 works on the keyword frequencies. Basically, the better the degree of the phrase match between the document body and the query, the higher is the phrase proximity (it maxes out when the document contains the entire query as a verbatim quote). And BM25 is higher when the document contains more rare words. We’ll save the detailed discussion for later.

Currently implemented rankers are:

  • SPH_RANK_PROXIMITY_BM25, the default ranking mode that uses and combines both phrase proximity and BM25 ranking.
  • SPH_RANK_BM25, statistical ranking mode which uses BM25 ranking only (similar to most other full-text engines). This mode is faster but may result in worse quality on queries which contain more than 1 keyword.
  • SPH_RANK_NONE, no ranking mode. This mode is obviously the fastest. A weight of 1 is assigned to all matches. This is sometimes called boolean searching that just matches the documents but does not rank them.
  • SPH_RANK_WORDCOUNT, ranking by the keyword occurrences count. This ranker computes the per-field keyword occurrence counts, then multiplies them by field weights, and sums the resulting values.
  • SPH_RANK_PROXIMITY returns raw phrase proximity value as a result. This mode is internally used to emulate SPH_MATCH_ALL queries.
  • SPH_RANK_MATCHANY returns rank as it was computed in SPH_MATCH_ANY mode earlier, and is internally used to emulate SPH_MATCH_ANY queries.
  • SPH_RANK_FIELDMASK returns a 32-bit mask with N-th bit corresponding to N-th fulltext field, numbering from 0. The bit will only be set when the respective field has any keyword occurrences satisfying the query.
  • SPH_RANK_SPH04 is generally based on the default SPH_RANK_PROXIMITY_BM25 ranker, but additionally boosts the matches when they occur in the very beginning or the very end of a text field. Thus, if a field equals the exact query, SPH04 should rank it higher than a field that contains the exact query but is not equal to it. (For instance, when the query is “Hyde Park”, a document entitled “Hyde Park” should be ranked higher than a one entitled “Hyde Park, London” or “The Hyde Park Cafe”.)
  • SPH_RANK_EXPR lets you specify the ranking formula in run time. It exposes a number of internal text factors and lets you define how the final weight should be computed from those factors. You can find more details about its syntax and a reference available factors in a subsection below.

You should specify the SPH_RANK_ prefix and use capital letters only when using the SetRankingMode() call from the SphinxAPI. The API ports expose these as global constants. Using SphinxQL syntax, the prefix should be omitted and the ranker name is case insensitive. Example:

// SphinxAPI
$client->SetRankingMode ( SPH_RANK_SPH04 );

// SphinxQL
mysql_query ( "SELECT ... OPTION ranker=sph04" );
Legacy matching modes rankers

Legacy matching modes automatically select a ranker as follows:

  • SPH_MATCH_ALL uses SPH_RANK_PROXIMITY ranker;
  • SPH_MATCH_ANY uses SPH_RANK_MATCHANY ranker;
  • SPH_MATCH_PHRASE uses SPH_RANK_PROXIMITY ranker;
  • SPH_MATCH_BOOLEAN uses SPH_RANK_NONE ranker.

Quick summary of the ranking factors

Name Level Type Summary
max_lcs query int maximum possible LCS value for the current query
bm25 document int quick estimate of BM25(1.2, 0) without syntax support
bm25a(k1, b) document int precise BM25() value with configurable K1, B constants and syntax support
bm25f(k1, b, {field=weight, …}) document int precise BM25F() value with extra configurable field weights
field_mask document int bit mask of matched fields
query_word_count document int number of unique inclusive keywords in a query
doc_word_count document int number of unique keywords matched in the document
lcs field int Longest Common Subsequence between query and document, in words
user_weight field int user field weight
hit_count field int total number of keyword occurrences
word_count field int number of unique matched keywords
tf_idf field float sum(tf*idf) over matched keywords == sum(idf) over occurrences
min_hit_pos field int first matched occurrence position, in words, 1-based
min_best_span_pos field int first maximum LCS span position, in words, 1-based
exact_hit field bool whether query == field
min_idf field float min(idf) over matched keywords
max_idf field float max(idf) over matched keywords
sum_idf field float sum(idf) over matched keywords
exact_order field bool whether all query keywords were a) matched and b) in query order
min_gaps field int minimum number of gaps between the matched keywords over the matching spans
lccs field int Longest Common Contiguous Subsequence between query and document, in words
wlccs field float Weighted Longest Common Contiguous Subsequence, sum(idf) over contiguous keyword spans
atc field float Aggregate Term Closeness, log(1+sum(idf1*idf2*pow(distance, -1.75)) over the best pairs of keywords

Document-level ranking factors

A document-level factor is a numeric value computed by the ranking engine for every matched document with regards to the current query. So it differs from a plain document attribute in that the attribute do not depend on the full text query, while factors might. Those factors can be used anywhere in the ranking expression. Currently implemented document-level factors are:

  • bm25 (integer), a document-level BM25 estimate (computed without keyword occurrence filtering).
  • max_lcs (integer), a query-level maximum possible value that the sum(lcs*user_weight) expression can ever take. This can be useful for weight boost scaling. For instance, MATCHANY ranker formula uses this to guarantee that a full phrase match in any field ranks higher than any combination of partial matches in all fields.
  • field_mask (integer), a document-level 32-bit mask of matched fields.
  • query_word_count (integer), the number of unique keywords in a query, adjusted for a number of excluded keywords. For instance, both (one one one one) and (one !two) queries should assign a value of 1 to this factor, because there is just one unique non-excluded keyword.
  • doc_word_count (integer), the number of unique keywords matched in the entire document.

Field-level ranking factors

A field-level factor is a numeric value computed by the ranking engine for every matched in-document text field with regards to the current query. As more than one field can be matched by a query, but the final weight needs to be a single integer value, these values need to be folded into a single one. To achieve that, field-level factors can only be used within a field aggregation function, they can not be used anywhere in the expression. For example, you can not use (lcs+bm25) as your ranking expression, as lcs takes multiple values (one in every matched field). You should use (sum(lcs)+bm25) instead, that expression sums lcs over all matching fields, and then adds bm25 to that per-field sum. Currently implemented field-level factors are:

  • lcs (integer), the length of a maximum verbatim match between the document and the query, counted in words. LCS stands for Longest Common Subsequence (or Subset). Takes a minimum value of 1 when only stray keywords were matched in a field, and a maximum value of query keywords count when the entire query was matched in a field verbatim (in the exact query keywords order). For example, if the query is ‘hello world’ and the field contains these two words quoted from the query (that is, adjacent to each other, and exactly in the query order), lcs will be 2. For example, if the query is ‘hello world program’ and the field contains ‘hello world’, lcs will be 2. Note that any subset of the query keyword works, not just a subset of adjacent keywords. For example, if the query is ‘hello world program’ and the field contains ‘hello (test program)’, lcs will be 2 just as well, because both ‘hello’ and ‘program’ matched in the same respective positions as they were in the query. Finally, if the query is ‘hello world program’ and the field contains ‘hello world program’, lcs will be 3. (Hopefully that is unsurprising at this point.)

  • user_weight (integer), the user specified per-field weight (refer to SetFieldWeights() in SphinxAPI and OPTION field_weights in SphinxQL respectively). The weights default to 1 if not specified explicitly.

  • hit_count (integer), the number of keyword occurrences that matched in the field. Note that a single keyword may occur multiple times. For example, if ‘hello’ occurs 3 times in a field and ‘world’ occurs 5 times, hit_count will be 8.

  • word_count (integer), the number of unique keywords matched in the field. For example, if ‘hello’ and ‘world’ occur anywhere in a field, word_count will be 2, irregardless of how many times do both keywords occur.

  • tf_idf (float), the sum of TF/IDF over all the keywords matched in the field. IDF is the Inverse Document Frequency, a floating point value between 0 and 1 that describes how frequent is the keywords (basically, 0 for a keyword that occurs in every document indexed, and 1 for a unique keyword that occurs in just a single document). TF is the Term Frequency, the number of matched keyword occurrences in the field. As a side note, tf_idf is actually computed by summing IDF over all matched occurrences. That’s by construction equivalent to summing TF*IDF over all matched keywords.

  • min_hit_pos (integer), the position of the first matched keyword occurrence, counted in words. Indexing begins from position 1.

  • min_best_span_pos (integer), the position of the first maximum LCS occurrences span. For example, assume that our query was ‘hello world program’ and ‘hello world’ subphrase was matched twice in the field, in positions 13 and 21. Assume that ‘hello’ and ‘world’ additionally occurred elsewhere in the field, but never next to each other and thus never as a subphrase match. In that case, min_best_span_pos will be 13. Note how for the single keyword queries min_best_span_pos will always equal min_hit_pos.

  • exact_hit (boolean), whether a query was an exact match of the entire current field. Used in the SPH04 ranker.

  • min_idf, max_idf, and sum_idf (float). These factors respectively represent the min(idf), max(idf) and sum(idf) over all keywords that were matched in the field.

  • exact_order (boolean). Whether all of the query keywords were matched in the field in the exact query order. For example, (microsoft office) query would yield exact_order=1 in a field with the following contents: (We use Microsoft software in our office.). However, the very same query in a (Our office is Microsoft free.) field would yield exact_order=0.

  • min_gaps (integer), the minimum number of positional gaps between (just) the keywords matched in field. Always 0 when less than 2 keywords match; always greater or equal than 0 otherwise.

    For example, with a [big wolf] query, [big bad wolf] field would yield min_gaps=1; [big bad hairy wolf] field would yield min_gaps=2; [the wolf was scary and big] field would yield min_gaps=3; etc. However, a field like [i heard a wolf howl] would yield min_gaps=0, because only one keyword would be matching in that field, and, naturally, there would be no gaps between the _matched_keywords.

    Therefore, this is a rather low-level, “raw” factor that you would most likely want to adjust before actually using for ranking. Specific adjustments depend heavily on your data and the resulting formula, but here are a few ideas you can start with: (a) any min_gaps based boosts could be simply ignored when word_count<2; (b) non-trivial min_gaps values (i.e. when word_count>=2) could be clamped with a certain “worst case” constant while trivial values (i.e. when min_gaps=0 and word_count<2) could be replaced by that constant; (c) a transfer function like 1/(1+min_gaps) could be applied (so that better, smaller min_gaps values would maximize it and worse, bigger min_gaps values would fall off slowly); and so on.

  • lccs (integer). Longest Common Contiguous Subsequence. A length of the longest subphrase that is common between the query and the document, computed in keywords.

    LCCS factor is rather similar to LCS but more restrictive, in a sense. While LCS could be greater than 1 though no two query words are matched next to each other, LCCS would only get greater than 1 if there are exact, contiguous query subphrases in the document. For example, (one two three four five) query vs (one hundred three hundred five hundred) document would yield lcs=3, but lccs=1, because even though mutual dispositions of 3 keywords (one, three, five) match between the query and the document, no 2 matching positions are actually next to each other.

    Note that LCCS still does not differentiate between the frequent and rare keywords; for that, see WLCCS.

  • wlccs (float). Weighted Longest Common Contiguous Subsequence. A sum of IDFs of the keywords of the longest subphrase that is common between the query and the document.

    WLCCS is computed very similarly to LCCS, but every “suitable” keyword occurrence increases it by the keyword IDF rather than just by 1 (which is the case with LCS and LCCS). That lets us rank sequences of more rare and important keywords higher than sequences of frequent keywords, even if the latter are longer. For example, a query (Zanzibar bed and breakfast) would yield lccs=1 for a (hotels of Zanzibar) document, but lccs=3 against (London bed and breakfast), even though “Zanzibar” is actually somewhat more rare than the entire “bed and breakfast” phrase. WLCCS factor alleviates that problem by using the keyword frequencies.

  • atc (float). Aggregate Term Closeness. A proximity based measure that grows higher when the document contains more groups of more closely located and more important (rare) query keywords. WARNING: you should use ATC with OPTION idf=‘plain,tfidf_unnormalized’; otherwise you would get unexpected results.

    ATC basically works as follows. For every keyword occurrence in the document, we compute the so called term closeness. For that, we examine all the other closest occurrences of all the query keywords (keyword itself included too) to the left and to the right of the subject occurrence, compute a distance dampening coefficient as k = pow(distance, -1.75) for those occurrences, and sum the dampened IDFs. Thus for every occurrence of every keyword, we get a “closeness” value that describes the “neighbors” of that occurrence. We then multiply those per-occurrence closenesses by their respective subject keyword IDF, sum them all, and finally, compute a logarithm of that sum.

    Or in other words, we process the best (closest) matched keyword pairs in the document, and compute pairwise “closenesses” as the product of their IDFs scaled by the distance coefficient:

    pair_tc = idf(pair_word1) * idf(pair_word2) * pow(pair_distance, -1.75)
    

    We then sum such closenesses, and compute the final, log-dampened ATC value:

    atc = log(1+sum(pair_tc))
    

    Note that this final dampening logarithm is exactly the reason you should use OPTION idf=plain, because without it, the expression inside the log() could be negative.

    Having closer keyword occurrences actually contributes much more to ATC than having more frequent keywords. Indeed, when the keywords are right next to each other, distance=1 and k=1; when there just one word in between them, distance=2 and k=0.297, with two words between, distance=3 and k=0.146, and so on. At the same time IDF attenuates somewhat slower. For example, in a 1 million document collection, the IDF values for keywords that match in 10, 100, and 1000 documents would be respectively 0.833, 0.667, and 0.500. So a keyword pair with two rather rare keywords that occur in just 10 documents each but with 2 other words in between would yield pair_tc = 0.101 and thus just barely outweigh a pair with a 100-doc and a 1000-doc keyword with 1 other word between them and pair_tc = 0.099. Moreover, a pair of two unique, 1-doc keywords with 3 words between them would get a pair_tc = 0.088 and lose to a pair of two 1000-doc keywords located right next to each other and yielding a pair_tc = 0.25. So, basically, while ATC does combine both keyword frequency and proximity, it is still somewhat favoring the proximity.

Ranking factor aggregation functions

A field aggregation function is a single argument function that takes an expression with field-level factors, iterates it over all the matched fields, and computes the final results. Currently implemented field aggregation functions are:

  • sum, sums the argument expression over all matched fields. For instance, sum(1) should return a number of matched fields.
  • top, returns the greatest value of the argument over all matched fields.

Formula expressions for all the built-in rankers

Most of the other rankers can actually be emulated with the expression based ranker. You just need to pass a proper expression. Such emulation is, of course, going to be slower than using the built-in, compiled ranker but still might be of interest if you want to fine-tune your ranking formula starting with one of the existing ones. Also, the formulas define the nitty gritty ranker details in a nicely readable fashion.

  • SPH_RANK_PROXIMITY_BM25 = sum(lcsuser_weight)1000+bm25
  • SPH_RANK_BM25 = bm25
  • SPH_RANK_NONE = 1
  • SPH_RANK_WORDCOUNT = sum(hit_count*user_weight)
  • SPH_RANK_PROXIMITY = sum(lcs*user_weight)
  • SPH_RANK_MATCHANY = sum((word_count+(lcs-1)max_lcs)user_weight)
  • SPH_RANK_FIELDMASK = field_mask
  • SPH_RANK_SPH04 = sum((4lcs+2(min_hit_pos==1)+exact_hit)*user_weight)*1000+bm25

Expressions, functions, and operators

Manticore lets you use arbitrary arithmetic expressions both via SphinxQL and SphinxAPI, involving attribute values, internal attributes (document ID and relevance weight), arithmetic operations, a number of built-in functions, and user-defined functions. This section documents the supported operators and functions. Here’s the complete reference list for quick access.

Operators

  • Arithmetic operators: +, -, *, /, %, DIV, MOD

    The standard arithmetic operators. Arithmetic calculations involving those can be performed in three different modes: (a) using single-precision, 32-bit IEEE 754 floating point values (the default), (**) using signed 32-bit integers, (c) using 64-bit signed integers. The expression parser will automatically switch to integer mode if there are no operations the result in a floating point value. Otherwise, it will use the default floating point mode. For instance, a+b will be computed using 32-bit integers if both arguments are 32-bit integers; or using 64-bit integers if both arguments are integers but one of them is 64-bit; or in floats otherwise. However, a/** or sqrt(a) will always be computed in floats, because these operations return a result of non-integer type. To avoid the first, you can either use IDIV(a,**) or a DIV b form. Also, a*b will not be automatically promoted to 64-bit when the arguments are 32-bit. To enforce 64-bit results, you can use BIGINT(). (But note that if there are non-integer operations, BIGINT() will simply be ignored.)

  • Comparison operators: <, > <=, >=, =, <>

    Comparison operators (eg. = or <=) return 1.0 when the condition is true and 0.0 otherwise. For instance, (a=b)+3 will evaluate to 4 when attribute ‘a’ is equal to attribute ‘b’, and to 3 when ‘a’ is not. Unlike MySQL, the equality comparisons (ie. = and <> operators) introduce a small equality threshold (1e-6 by default). If the difference between compared values is within the threshold, they will be considered equal.

  • Boolean operators: AND, OR, NOT

    Boolean operators (AND, OR, NOT) behave as usual. They are left-associative and have the least priority compared to other operators. NOT has more priority than AND and OR but nevertheless less than any other operator. AND and OR have the same priority so brackets use is recommended to avoid confusion in complex expressions.

  • Bitwise operators: &, |

    These operators perform bitwise AND and OR respectively. The operands must be of an integer types.

Numeric functions

  • ABS()

    Returns the absolute value of the argument.

  • BITDOT()

    BITDOT(mask, w0, w1, …) returns the sum of products of an each bit of a mask multiplied with its weight. bit0*w0 + bit1*w1 + ...

  • CEIL()

    Returns the smallest integer value greater or equal to the argument.

  • CONTAINS()

    CONTAINS(polygon, x, y) checks whether the (x,y) point is within the given polygon, and returns 1 if true, or 0 if false. The polygon has to be specified using either the POLY2D() function or the GEOPOLY2D() function. The former function is intended for “small” polygons, meaning less than 500 km (300 miles) a side, and it doesn’t take into account the Earth’s curvature for speed. For larger distances, you should use GEOPOLY2D, which tessellates the given polygon in smaller parts, accounting for the Earth’s curvature.

  • COS()

    Returns the cosine of the argument.

  • DOUBLE() Forcibly promotes given argument to floating point type. Intended to help enforce evaluation of numeric JSON fields.
  • EXP()

    Returns the exponent of the argument (e=2.718… to the power of the argument).

  • FIBONACCI()

    Returns the N-th Fibonacci number, where N is the integer argument. That is, arguments of 0 and up will generate the values 0, 1, 1, 2, 3, 5, 8, 13 and so on. Note that the computations are done using 32-bit integer math and thus numbers 48th and up will be returned modulo 2^32.

  • FLOOR()

    Returns the largest integer value lesser or equal to the argument.

  • GEOPOLY2D()

    GEOPOLY2D(x1,y1,x2,y2,x3,y3…) produces a polygon to be used with the CONTAINS() function. This function takes into account the Earth’s curvature by tessellating the polygon into smaller ones, and should be used for larger areas; see the POLY2D() function. The function expects coordinates to be in degrees, if radians are used it will give same result as POLY2D().

  • IDIV()

    Returns the result of an integer division of the first argument by the second argument. Both arguments must be of an integer type.

  • LN()

    Returns the natural logarithm of the argument (with the base of e=2.718…).

  • LOG10()

    Returns the common logarithm of the argument (with the base of 10).

  • LOG2()

    Returns the binary logarithm of the argument (with the base of 2).

  • MAX()

    Returns the bigger of two arguments.

  • MIN()

    Returns the smaller of two arguments.

  • POLY2D()

    POLY2D(x1,y1,x2,y2,x3,y3…) produces a polygon to be used with the CONTAINS() function. This polygon assumes a flat Earth, so it should not be too large; see the POLY2D() function.

  • POW()

    Returns the first argument raised to the power of the second argument.

  • SIN()

    Returns the sine of the argument.

  • SQRT()

    Returns the square root of the argument.

  • UINT()

    Forcibly reinterprets given argument to 64-bit unsigned type.

Date and time functions

  • DAY()

    Returns the integer day of month (in 1..31 range) from a timestamp argument, according to the current timezone.

  • MONTH()

    Returns the integer month (in 1..12 range) from a timestamp argument, according to the current timezone.

  • NOW()

    Returns the current timestamp as an INTEGER.

  • YEAR()

    Returns the integer year (in 1969..2038 range) from a timestamp argument, according to the current timezone.

  • YEARMONTH()

    Returns the integer year and month code (in 196912..203801 range) from a timestamp argument, according to the current timezone.

  • YEARMONTHDAY()

    Returns the integer year, month, and date code (in 19691231..20380119 range) from a timestamp argument, according to the current timezone.

  • SECOND()

    Returns the integer second (in 0..59 range) from a timestamp argument, according to the current timezone.

  • MINUTE()

    Returns the integer minute (in 0..59 range) from a timestamp argument, according to the current timezone.

  • HOUR()

    Returns the integer hour (in 0..23 range) from a timestamp argument, according to the current timezone.

Type conversion functions

  • BIGINT()

    Forcibly promotes the integer argument to 64-bit type, and does nothing on floating point argument. It’s intended to help enforce evaluation of certain expressions (such as a*b) in 64-bit mode even though all the arguments are 32-bit.

  • INTEGER()

    Forcibly promotes given argument to 64-bit signed type. Intended to help enforce evaluation of numeric JSON fields.

  • SINT()

    Forcibly reinterprets its 32-bit unsigned integer argument as signed, and also expands it to 64-bit type (because 32-bit type is unsigned). It’s easily illustrated by the following example: 1-2 normally evaluates to 4294967295, but SINT(1-2) evaluates to -1.

Comparison functions

  • IF()

    IF() behavior is slightly different that that of its MySQL counterpart. It takes 3 arguments, check whether the 1st argument is equal to 0.0, returns the 2nd argument if it is not zero, or the 3rd one when it is. Note that unlike comparison operators, IF() does not use a threshold! Therefore, it’s safe to use comparison results as its 1st argument, but arithmetic operators might produce unexpected results. For instance, the following two calls will produce different results even though they are logically equivalent:

    IF ( sqrt(3)*sqrt(3)-3<>0, a, b )
    IF ( sqrt(3)*sqrt(3)-3, a, b )

In the first case, the comparison operator <> will return 0.0 (false)
because of a threshold, and ``IF()`` will always return ‘**’ as a
result. In the second one, the same ``sqrt(3)*sqrt(3)-3`` expression
will be compared with zero *without* threshold by the ``IF()``
function itself. But its value will be slightly different from zero
because of limited floating point calculations precision. Because of
that, the comparison with 0.0 done by ``IF()`` will not pass, and the
second variant will return ‘a’ as a result.
  • IN()

    IN(expr,val1,val2,…) takes 2 or more arguments, and returns 1 if 1st argument (expr) is equal to any of the other arguments (val1..valN), or 0 otherwise. Currently, all the checked values (but not the expression itself!) are required to be constant. (Its technically possible to implement arbitrary expressions too, and that might be implemented in the future.) Constants are pre-sorted and then binary search is used, so IN() even against a big arbitrary list of constants will be very quick. First argument can also be a MVA attribute. In that case, IN() will return 1 if any of the MVA values is equal to any of the other arguments. IN() also supports IN(expr,@uservar) syntax to check whether the value belongs to the list in the given global user variable. First argument can be JSON attribute.

  • INTERVAL()

    INTERVAL(expr,point1,point2,point3,…), takes 2 or more arguments, and returns the index of the argument that is less than the first argument: it returns 0 if expr<point1, 1 if point1<=expr<point2, and so on. It is required that point1<point2<…<pointN for this function to work correctly.

Miscellaneous functions

  • ALL()

    ALL(cond FOR var IN json.array) applies to JSON arrays and returns 1 if condition is true for all elements in array and 0 otherwise. ‘cond’ is a general expression which additionally can use ‘var’ as current value of an array element within itself.

    SELECT ALL(x>3 AND x<7 FOR x IN j.intarray) FROM test;
    

    ALL(mva) is a special constructor for multi value attributes. When used in conjunction with comparison operators it returns 1 if all values compared are found among the MVA values.

    SELECT * FROM test WHERE ALL(mymva)>10;
    
  • ANY()

    ANY(cond FOR var IN json.array) works similar to ALL() except for it returns 1 if condition is true for any element in array.

    ANY(mva) is a special constructor for multi value attributes. When used in conjunction with comparison operators it returns 1 if any of the values compared are found among the MVA values. ANY is used by default if no constructor is used, however a warning will be raised about missing constructor.

  • ATAN2()

    Returns the arctangent function of two arguments, expressed in radians.

  • CRC32()

    Returns the CRC32 value of a string argument.

  • GEODIST()

    GEODIST(lat1, lon1, lat2, lon2, […]) function computes geosphere distance between two given points specified by their coordinates. Note that by default both latitudes and longitudes must be in radians and the result will be in meters. You can use arbitrary expression as any of the four coordinates. An optimized path will be selected when one pair of the arguments refers directly to a pair attributes and the other one is constant.

    GEODIST() also takes an optional 5th argument that lets you easily convert between input and output units, and pick the specific geodistance formula to use. The complete syntax and a few examples are as follows:

    GEODIST(lat1, lon1, lat2, lon2, { option=value, ... })
    
    GEODIST(40.7643929, -73.9997683, 40.7642578, -73.9994565, {in=degrees, out=feet})
    
    GEODIST(51.50, -0.12, 29.98, 31.13, {in=deg, out=mi}}
    

    The known options and their values are:

    • in = {deg | degrees | rad | radians}, specifies the input units;
    • out = {m | meters | km | kilometers | ft | feet | mi | miles}, specifies the output units;
    • method = {adaptive | haversine}, specifies the geodistance calculation method.

    The default method is “adaptive”. It is well optimized implementation that is both more precise and much faster at all times than “haversine”.

  • GREATEST()

    GREATEST(attr_json.some_array) function takes JSON array as the argument, and returns the greatest value in that array. Also works for MVA.

  • INDEXOF()

    INDEXOF(cond FOR var IN json.array) function iterates through all elements in array and returns index of first element for which ‘cond’ is true and -1 if ‘cond’ is false for every element in array.

SELECT INDEXOF(name='John' FOR name IN j.peoples) FROM test;
  • LEAST()

    LEAST(attr_json.some_array) function takes JSON array as the argument, and returns the least value in that array. Also works for MVA.

  • LENGTH()

    LENGTH(attr_mva) function returns amount of elements in MVA set. It works with both 32-bit and 64-bit MVA attributes. LENGTH(attr_json) returns length of a field in JSON. Return value depends on type of a field. For example LENGTH(json_attr.some_int) always returns 1 and LENGTH(json_attr.some_array) returns number of elements in array.

  • MIN_TOP_SORTVAL()

    Returns sort key value of the worst found element in the current top-N matches if sort key is float and 0 otherwise.

  • MIN_TOP_WEIGHT() Returns weight of the worst found element in the current top-N matches.
  • PACKEDFACTORS()

    PACKEDFACTORS() can be used in queries, either to just see all the weighting factors calculated when doing the matching, or to provide a binary attribute that can be used to write a custom ranking UDF. This function works only if expression ranker is specified and the query is not a full scan, otherwise it will return an error. PACKEDFACTORS() can take an optional argument that disables ATC ranking factor calculation:

    PACKEDFACTORS({no_atc=1})
    

    Calculating ATC slows down query processing considerably, so this option can be useful if you need to see the ranking factors, but do not need ATC. PACKEDFACTORS() can also be told to format its output as JSON:

    PACKEDFACTORS({json=1})
    

    The respective outputs in either key-value pair or JSON format would look as follows below. (Note that the examples below are wrapped for readability; actual returned values would be single-line.)

    mysql> SELECT id, PACKEDFACTORS() FROM test1
        -> WHERE MATCH('test one') OPTION ranker=expr('1') \G
    *************************** 1\. row ***************************
                 id: 1
    packedfactors(): bm25=569, bm25a=0.617197, field_mask=2, doc_word_count=2,
        field1=(lcs=1, hit_count=2, word_count=2, tf_idf=0.152356,
            min_idf=-0.062982, max_idf=0.215338, sum_idf=0.152356, min_hit_pos=4,
            min_best_span_pos=4, exact_hit=0, max_window_hits=1, min_gaps=2,
            exact_order=1, lccs=1, wlccs=0.215338, atc=-0.003974),
        word0=(tf=1, idf=-0.062982),
        word1=(tf=1, idf=0.215338)
    1 row in set (0.00 sec)
    
    mysql> SELECT id, PACKEDFACTORS({json=1}) FROM test1
        -> WHERE MATCH('test one') OPTION ranker=expr('1') \G
    *************************** 1\. row ***************************
                         id: 1
    packedfactors({json=1}):
    {
    
        "bm25": 569,
        "bm25a": 0.617197,
        "field_mask": 2,
        "doc_word_count": 2,
        "fields": [
            {
                "lcs": 1,
                "hit_count": 2,
                "word_count": 2,
                "tf_idf": 0.152356,
                "min_idf": -0.062982,
                "max_idf": 0.215338,
                "sum_idf": 0.152356,
                "min_hit_pos": 4,
                "min_best_span_pos": 4,
                "exact_hit": 0,
                "max_window_hits": 1,
                "min_gaps": 2,
                "exact_order": 1,
                "lccs": 1,
                "wlccs": 0.215338,
                "atc": -0.003974
            }
        ],
        "words": [
            {
                "tf": 1,
                "idf": -0.062982
            },
            {
                "tf": 1,
                "idf": 0.215338
            }
        ]
    
    }
    1 row in set (0.01 sec)
    

    This function can be used to implement custom ranking functions in UDFs, as in

    SELECT *, CUSTOM_RANK(PACKEDFACTORS()) AS r
    FROM my_index
    WHERE match('hello')
    ORDER BY r DESC
    OPTION ranker=expr('1');
    

    Where CUSTOM_RANK() is a function implemented in an UDF. It should declare a SPH_UDF_FACTORS structure (defined in sphinxudf.h), initialize this structure, unpack the factors into it before usage, and deinitialize it afterwards, as follows:

    SPH_UDF_FACTORS factors;
    sphinx_factors_init(&factors);
    sphinx_factors_unpack((DWORD*)args->arg_values[0], &factors);
    // ... can use the contents of factors variable here ...
    sphinx_factors_deinit(&factors);
    

    PACKEDFACTORS() data is available at all query stages, not just when doing the initial matching and ranking pass. That enables another particularly interesting application of PACKEDFACTORS(), namely re-ranking.

    In the example just above, we used an expression-based ranker with a dummy expression, and sorted the result set by the value computed by our UDF. In other words, we used the UDF to rank all our results. Assume now, for the sake of an example, that our UDF is extremely expensive to compute and has a throughput of just 10,000 calls per second. Assume that our query matches 1,000,000 documents. To maintain reasonable performance, we would then want to use a (much) simpler expression to do most of our ranking, and then apply the expensive UDF to only a few top results, say, top-100 results. Or, in other words, build top-100 results using a simpler ranking function and then re-rank those with a complex one. We can do that just as well with subselects:

    SELECT * FROM (
        SELECT *, CUSTOM_RANK(PACKEDFACTORS()) AS r
        FROM my_index WHERE match('hello')
        OPTION ranker=expr('sum(lcs)*1000+bm25')
        ORDER BY WEIGHT() DESC
        LIMIT 100
    ) ORDER BY r DESC LIMIT 10
    

    In this example, expression-based ranker will be called for every matched document to compute WEIGHT(). So it will get called 1,000,000 times. But the UDF computation can be postponed until the outer sort. And it also will be done for just the top-100 matches by WEIGHT(), according to the inner limit. So the UDF will only get called 100 times. And then the final top-10 matches by UDF value will be selected and returned to the application.

    For reference, in the distributed case PACKEDFACTORS() data gets sent from the agents to master in a binary format, too. This makes it technically feasible to implement additional re-ranking pass (or passes) on the master node, if needed.

    If used with SphinxQL but not called from any UDFs, the result of PACKEDFACTORS() is simply formatted as plain text, which can be used to manually assess the ranking factors. Note that this feature is not currently supported by the Manticore API.

  • REMAP()

    REMAP(condition, expression, (cond1, cond2, …), (expr1, expr2, …)) function allows you to make some exceptions of an expression values depending on condition values. Condition expression should always result integer, expression can result in integer or float.

SELECT REMAP(userid, karmapoints, (1, 67), (999, 0)) FROM users;
SELECT REMAP(id%10, salary, (0), (0.0)) FROM employes;
  • rand()

    RAND(seed) function returns a random float between 0..1. Optional, an integer seed value can be specified.

Sorting modes

There are the following result sorting modes available:

  • SPH_SORT_RELEVANCE mode, that sorts by relevance in descending order (best matches first);
  • SPH_SORT_ATTR_DESC mode, that sorts by an attribute in descending order (bigger attribute values first);
  • SPH_SORT_ATTR_ASC mode, that sorts by an attribute in ascending order (smaller attribute values first);
  • SPH_SORT_TIME_SEGMENTS mode, that sorts by time segments (last hour/day/week/month) in descending order, and then by relevance in descending order;
  • SPH_SORT_EXTENDED mode, that sorts by SQL-like combination of columns in ASC/DESC order;
  • SPH_SORT_EXPR mode, that sorts by an arithmetic expression.

SPH_SORT_RELEVANCE ignores any additional parameters and always sorts matches by relevance rank. All other modes require an additional sorting clause, with the syntax depending on specific mode. SPH_SORT_ATTR_ASC, SPH_SORT_ATTR_DESC and SPH_SORT_TIME_SEGMENTS modes require simply an attribute name. SPH_SORT_RELEVANCE is equivalent to sorting by “@weight DESC, @id ASC” in extended sorting mode, SPH_SORT_ATTR_ASC is equivalent to “attribute ASC, @weight DESC, @id ASC”, and SPH_SORT_ATTR_DESC to “attribute DESC, @weight DESC, @id ASC” respectively.

SPH_SORT_TIME_SEGMENTS mode

In SPH_SORT_TIME_SEGMENTS mode, attribute values are split into so-called time segments, and then sorted by time segment first, and by relevance second.

The segments are calculated according to the current timestamp at the time when the search is performed, so the results would change over time. The segments are as follows:

  • last hour,
  • last day,
  • last week,
  • last month,
  • last 3 months,
  • everything else.

These segments are hardcoded, but it is trivial to change them if necessary.

This mode was added to support searching through blogs, news headlines, etc. When using time segments, recent records would be ranked higher because of segment, but within the same segment, more relevant records would be ranked higher - unlike sorting by just the timestamp attribute, which would not take relevance into account at all.

SPH_SORT_EXTENDED mode

In SPH_SORT_EXTENDED mode, you can specify an SQL-like sort expression with up to 5 attributes (including internal attributes), eg:

@relevance DESC, price ASC, @id DESC

Both internal attributes (that are computed by the engine on the fly) and user attributes that were configured for this index are allowed. Internal attribute names must start with magic @-symbol; user attribute names can be used as is. In the example above, @relevance and @id are internal attributes and price is user-specified.

Known internal attributes are:

  • @id (match ID)
  • @weight (match weight)
  • @rank (match weight)
  • @relevance (match weight)
  • @random (return results in random order)

@rank and @relevance are just additional aliases to @weight.

SPH_SORT_EXPR mode

Expression sorting mode lets you sort the matches by an arbitrary arithmetic expression, involving attribute values, internal attributes (@id and @weight), arithmetic operations, and a number of built-in functions. Here’s an example:

$cl->SetSortMode ( SPH_SORT_EXPR,
    "@weight + ( user_karma + ln(pageviews) )*0.1" );

The operators and functions supported in the expressions are discussed in Expressions, functions, and operators.

Grouping (clustering) search results

Sometimes it could be useful to group (or in other terms, cluster) search results and/or count per-group match counts - for instance, to draw a nice graph of how much matching blog posts were there per each month; or to group Web search results by site; or to group matching forum posts by author; etc.

In theory, this could be performed by doing only the full-text search in Manticore and then using found IDs to group on SQL server side. However, in practice doing this with a big result set (10K-10M matches) would typically kill performance.

To avoid that, Manticore offers so-called grouping mode. It is enabled with SetGroupBy() API call. When grouping, all matches are assigned to different groups based on group-by value. This value is computed from specified attribute using one of the following built-in functions:

  • SPH_GROUPBY_DAY, extracts year, month and day in YYYYMMDD format from timestamp;
  • SPH_GROUPBY_WEEK, extracts year and first day of the week number (counting from year start) in YYYYNNN format from timestamp;
  • SPH_GROUPBY_MONTH, extracts month in YYYYMM format from timestamp;
  • SPH_GROUPBY_YEAR, extracts year in YYYY format from timestamp;
  • SPH_GROUPBY_ATTR, uses attribute value itself for grouping.

The final search result set then contains one best match per group. Grouping function value and per-group match count are returned along as “virtual” attributes named @group and @count respectively.

The result set is sorted by group-by sorting clause, with the syntax similar to `SPH_SORT_EXTENDED sorting clause <SPH_SORT_EXTENDED_mode>` syntax. In addition to @id and @weight, group-by sorting clause may also include:

  • @group (groupby function value),
  • @count (amount of matches in group).

The default mode is to sort by groupby value in descending order, ie. by @group desc.

On completion, total_found result parameter would contain total amount of matching groups over he whole index.

WARNING: grouping is done in fixed memory and thus its results are only approximate; so there might be more groups reported in total_found than actually present. @count might also be underestimated. To reduce inaccuracy, one should raise max_matches. If max_matches allows to store all found groups, results will be 100% correct.

For example, if sorting by relevance and grouping by "published" attribute with SPH_GROUPBY_DAY function, then the result set will contain

  • one most relevant match per each day when there were any matches published,
  • with day number and per-day match count attached,
  • sorted by day number in descending order (ie. recent days first).

Aggregate functions (AVG(), MIN(), MAX(), SUM()) are supported through SetSelect() API call when using GROUP BY.

Distributed searching

To scale well, Manticore has distributed searching capabilities. Distributed searching is useful to improve query latency (ie. search time) and throughput (ie. max queries/sec) in multi-server, multi-CPU or multi-core environments. This is essential for applications which need to search through huge amounts data (ie. billions of records and terabytes of text).

The key idea is to horizontally partition (HP) searched data across search nodes and then process it in parallel.

Partitioning is done manually. You should

  • setup several instances of Manticore programs (indexer and searchd) on different servers;
  • make the instances index (and search) different parts of data;
  • configure a special distributed index on some of the searchd instances;
  • and query this index.

This index only contains references to other local and remote indexes - so it could not be directly reindexed, and you should reindex those indexes which it references instead.

When searchd receives a query against distributed index, it does the following:

  1. connects to configured remote agents;
  2. issues the query;
  3. sequentially searches configured local indexes (while the remote agents are searching);
  4. retrieves remote agents’ search results;
  5. merges all the results together, removing the duplicates;
  6. sends the merged results to client.

From the application’s point of view, there are no differences between searching through a regular index, or a distributed index at all. That is, distributed indexes are fully transparent to the application, and actually there’s no way to tell whether the index you queried was distributed or local.

Any searchd instance could serve both as a master (which aggregates the results) and a slave (which only does local searching) at the same time. This has a number of uses:

  1. every machine in a cluster could serve as a master which searches the whole cluster, and search requests could be balanced between masters to achieve a kind of HA (high availability) in case any of the nodes fails;
  2. if running within a single multi-CPU or multi-core machine, there would be only 1 searchd instance querying itself as an agent and thus utilizing all CPUs/core.

It is scheduled to implement better HA support which would allow to specify which agents mirror each other, do health checks, keep track of alive agents, load-balance requests, etc.

Query log formats

Two query log formats are supported. Plain text format is still the default one. However, while it might be more convenient for manual monitoring and review, but hard to replay for benchmarks, it only logs search queries but not the other types of requests, does not always contain the complete search query data, etc. The default text format is also harder (and sometimes impossible) to replay for benchmarking purposes. The sphinxql format alleviates that. It aims to be complete and automatable, even though at the cost of brevity and readability.

Plain log format

By default, searchd logs all successfully executed search queries into a query log file. Here’s an example:

[Fri Jun 29 21:17:58 2007] 0.004 sec 0.004 sec [all/0/rel 35254 (0,20)] [lj] test
[Fri Jun 29 21:20:34 2007] 0.024 sec 0.024 sec [all/0/rel 19886 (0,20) @channel_id] [lj] test

This log format is as follows:

[query-date] real-time wall-time [match-mode/filters-count/sort-mode
    total-matches (offset,limit) @groupby-attr] [index-name] query
  • real-time is a time measured just from start to finish of the query
  • wall-time like real-time but not including waiting for agents and merging result sets time

Match mode can take one of the following values:

  • “all” for SPH_MATCH_ALL mode;
  • “any” for SPH_MATCH_ANY mode;
  • “phr” for SPH_MATCH_PHRASE mode;
  • “bool” for SPH_MATCH_BOOLEAN mode;
  • “ext” for SPH_MATCH_EXTENDED mode;
  • “ext2” for SPH_MATCH_EXTENDED2 mode;
  • “scan” if the full scan mode was used, either by being specified with SPH_MATCH_FULLSCAN, or if the query was empty (as documented under Matching Modes)

Sort mode can take one of the following values:

  • “rel” for SPH_SORT_RELEVANCE mode;
  • “attr-” for SPH_SORT_ATTR_DESC mode;
  • “attr+” for SPH_SORT_ATTR_ASC mode;
  • “tsegs” for SPH_SORT_TIME_SEGMENTS mode;
  • “ext” for SPH_SORT_EXTENDED mode.

Additionally, if searchd was started with --iostats, there will be a block of data after where the index(es) searched are listed.

A query log entry might take the form of:

[Fri Jun 29 21:17:58 2007] 0.004 sec [all/0/rel 35254 (0,20)] [lj]
   [ios=6 kb=111.1 ms=0.5] test

This additional block is information regarding I/O operations in performing the search: the number of file I/O operations carried out, the amount of data in kilobytes read from the index files and time spent on I/O operations (although there is a background processing component, the bulk of this time is the I/O operation time).

SphinxQL log format

This new log format introduced with the goals begin logging everything and then some, and in a format easy to automate (for instance, automatically replay). SphinxQL log format can either be enabled via the query_log_format directive in the configuration file, or switched back and forth on the fly with the SET GLOBAL query_log_format=… statement via SphinxQL. In the new format, the example from the previous section would look as follows. (Wrapped below for readability, but with just one query per line in the actual log.)

/* Fri Jun 29 21:17:58.609 2007 2011 conn 2 real 0.004 wall 0.004 found 35254 */
SELECT * FROM lj WHERE MATCH('test') OPTION ranker=proximity;

/* Fri Jun 29 21:20:34 2007.555 conn 3 real 0.024 wall 0.024 found 19886 */
SELECT * FROM lj WHERE MATCH('test') GROUP BY channel_id
OPTION ranker=proximity;

Note that all requests would be logged in this format, including those sent via SphinxAPI and SphinxSE, not just those sent via SphinxQL. Also note, that this kind of logging works only with plain log files and will not work if you use ‘syslog’ service for logging.

The features of SphinxQL log format compared to the default text one are as follows.

  • All request types should be logged. (This is still work in progress.)
  • Full statement data will be logged where possible.
  • Errors and warnings are logged.
  • The log should be automatically replayable via SphinxQL.
  • Additional performance counters (currently, per-agent distributed query times) are logged.

Use sphinxql:compact_in to shorten your IN() clauses in log if you have too much values in it.

Every request (including both SphinxAPI and SphinxQL) request must result in exactly one log line. All request types, including INSERT, CALL SNIPPETS, etc will eventually get logged, though as of time of this writing, that is a work in progress). Every log line must be a valid SphinxQL statement that reconstructs the full request, except if the logged request is too big and needs shortening for performance reasons. Additional messages, counters, etc can be logged in the comments section after the request.

MySQL protocol support and SphinxQL

Manticore searchd daemon supports MySQL binary network protocol and can be accessed with regular MySQL API. For instance, ‘mysql’ CLI client program works well. Here’s an example of querying Manticore using MySQL client:

$ mysql -P 9306
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 0.9.9-dev (r1734)

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql> SELECT * FROM test1 WHERE MATCH('test')
    -> ORDER BY group_id ASC OPTION ranker=bm25;
+------+--------+----------+------------+
| id   | weight | group_id | date_added |
+------+--------+----------+------------+
|    4 |   1442 |        2 | 1231721236 |
|    2 |   2421 |      123 | 1231721236 |
|    1 |   2421 |      456 | 1231721236 |
+------+--------+----------+------------+
3 rows in set (0.00 sec)

Note that mysqld was not even running on the test machine. Everything was handled by searchd itself.

The new access method is supported in addition to native APIs which all still work perfectly well. In fact, both access methods can be used at the same time. Also, native API is still the default access method. MySQL protocol support needs to be additionally configured. This is a matter of 1-line config change, adding a new listener with mysql41 specified as a protocol:

listen = localhost:9306:mysql41

Just supporting the protocol and not the SQL syntax would be useless so Manticore now also supports a subset of SQL that we dubbed SphinxQL. It supports the standard querying all the index types with SELECT, modifying RT indexes with INSERT, REPLACE, and DELETE, and much more. Full SphinxQL reference is available in SphinxQL reference.

Multi-queries

Multi-queries, or query batches, let you send multiple queries to Manticore in one go (more formally, one network request).

Two API methods that implement multi-query mechanism are AddQuery() and RunQueries(). You can also run multiple queries with SphinxQL, see the section called :ref:`multi-statement_queries. (In fact, regular Query() call is internally implemented as a single AddQuery() call immediately followed by RunQueries() call.) AddQuery() captures the current state of all the query settings set by previous API calls, and memorizes the query. RunQueries() actually sends all the memorized queries, and returns multiple result sets. There are no restrictions on the queries at all, except just a sanity check on a number of queries in a single batch (see max_batch_queries).

Why use multi-queries? Generally, it all boils down to performance. First, by sending requests to searchd in a batch instead of one by one, you always save a bit by doing less network roundtrips. Second, and somewhat more important, sending queries in a batch enables searchd to perform certain internal optimizations. As new types of optimizations are being added over time, it generally makes sense to pack all the queries into batches where possible, so that simply upgrading Manticore to a new version would automatically enable new optimizations. In the case when there aren’t any possible batch optimizations to apply, queries will be processed one by one internally.

Why (or rather when) not use multi-queries? Multi-queries requires all the queries in a batch to be independent, and sometimes they aren’t. That is, sometimes query B is based on query A results, and so can only be set up after executing query A. For instance, you might want to display results from a secondary index if and only if there were no results found in a primary index. Or maybe just specify offset into 2nd result set based on the amount of matches in the 1st result set. In that case, you will have to use separate queries (or separate batches).

There are two major optimizations to be aware of: common query optimization and common subtree optimization.

Common query optimization means that searchd will identify all those queries in a batch where only the sorting and group-by settings differ, and only perform searching once. For instance, if a batch consists of 3 queries, all of them are for “ipod nano”, but 1st query requests top-10 results sorted by price, 2nd query groups by vendor ID and requests top-5 vendors sorted by rating, and 3rd query requests max price, full-text search for “ipod nano” will only be performed once, and its results will be reused to build 3 different result sets.

So-called faceted searching is a particularly important case that benefits from this optimization. Indeed, faceted searching can be implemented by running a number of queries, one to retrieve search results themselves, and a few other ones with same full-text query but different group-by settings to retrieve all the required groups of results (top-3 authors, top-5 vendors, etc). And as long as full-text query and filtering settings stay the same, common query optimization will trigger, and greatly improve performance.

Common subtree optimization is even more interesting. It lets searchd exploit similarities between batched full-text queries. It identifies common full-text query parts (subtrees) in all queries, and caches them between queries. For instance, look at the following query batch:

donald trump president
donald trump barack obama john mccain
donald trump speech

There’s a common two-word part (“donald trump”) that can be computed only once, then cached and shared across the queries. And common subtree optimization does just that. Per-query cache size is strictly controlled by subtree_docs_cache and subtree_hits_cache directives (so that caching all sixteen gazillions of documents that match “i am” does not exhaust the RAM and instantly kill your server).

Here’s a code sample (in PHP) that fire the same query in 3 different sorting modes:

require ( "sphinxapi.php" );
$cl = new ManticoreClient ();
$cl->SetMatchMode ( SPH_MATCH_EXTENDED );

$cl->SetSortMode ( SPH_SORT_RELEVANCE );
$cl->AddQuery ( "the", "lj" );
$cl->SetSortMode ( SPH_SORT_EXTENDED, "published desc" );
$cl->AddQuery ( "the", "lj" );
$cl->SetSortMode ( SPH_SORT_EXTENDED, "published asc" );
$cl->AddQuery ( "the", "lj" );
$res = $cl->RunQueries();

How to tell whether the queries in the batch were actually optimized? If they were, respective query log will have a “multiplier” field that specifies how many queries were processed together:

[Sun Jul 12 15:18:17.000 2009] 0.040 sec x3 [ext/0/rel 747541 (0,20)] [lj] the
[Sun Jul 12 15:18:17.000 2009] 0.040 sec x3 [ext/0/ext 747541 (0,20)] [lj] the
[Sun Jul 12 15:18:17.000 2009] 0.040 sec x3 [ext/0/ext 747541 (0,20)] [lj] the

Note the “x3” field. It means that this query was optimized and processed in a sub-batch of 3 queries. For reference, this is how the regular log would look like if the queries were not batched:

[Sun Jul 12 15:18:17.062 2009] 0.059 sec [ext/0/rel 747541 (0,20)] [lj] the
[Sun Jul 12 15:18:17.156 2009] 0.091 sec [ext/0/ext 747541 (0,20)] [lj] the
[Sun Jul 12 15:18:17.250 2009] 0.092 sec [ext/0/ext 747541 (0,20)] [lj] the

Note how per-query time in multi-query case was improved by a factor of 1.5x to 2.3x, depending on a particular sorting mode. In fact, for both common query and common subtree optimizations, there were reports of 3x and even more improvements, and that’s from production instances, not just synthetic tests.

Collations

Collations essentially affect the string attribute comparisons. They specify both the character set encoding and the strategy that Manticore uses to compare strings when doing ORDER BY or GROUP BY with a string attribute involved.

String attributes are stored as is when indexing, and no character set or language information is attached to them. That’s okay as long as Manticore only needs to store and return the strings to the calling application verbatim. But when you ask Manticore to sort by a string value, that request immediately becomes quite ambiguous.

First, single-byte (ASCII, or ISO-8859-1, or Windows-1251) strings need to be processed differently that the UTF-8 ones that may encode every character with a variable number of bytes. So we need to know what is the character set type to interpret the raw bytes as meaningful characters properly.

Second, we additionally need to know the language-specific string sorting rules. For instance, when sorting according to US rules in en_US locale, the accented character ‘ï’ (small letter i with diaeresis) should be placed somewhere after ‘z’. However, when sorting with French rules and fr_FR locale in mind, it should be placed between ‘i’ and ‘j’. And some other set of rules might choose to ignore accents at all, allowing ‘ï’ and ‘i’ to be mixed arbitrarily.

Third, but not least, we might need case-sensitive sorting in some scenarios and case-insensitive sorting in some others.

Collations combine all of the above: the character set, the language rules, and the case sensitivity. Manticore currently provides the following four collations.

  1. libc_ci
  2. libc_cs
  3. utf8_general_ci
  4. binary

The first two collations rely on several standard C library (libc) calls and can thus support any locale that is installed on your system. They provide case-insensitive (_ci) and case-sensitive (_cs) comparisons respectively. By default they will use C locale, effectively resorting to bytewise comparisons. To change that, you need to specify a different available locale using collation_libc_locale directive. The list of locales available on your system can usually be obtained with the locale command:

$ locale -a
C
en_AG
en_AU.utf8
en_BW.utf8
en_CA.utf8
en_DK.utf8
en_GB.utf8
en_HK.utf8
en_IE.utf8
en_IN
en_NG
en_NZ.utf8
en_PH.utf8
en_SG.utf8
en_US.utf8
en_ZA.utf8
en_ZW.utf8
es_ES
fr_FR
POSIX
ru_RU.utf8
ru_UA.utf8

The specific list of the system locales may vary. Consult your OS documentation to install additional needed locales.

utf8_general_ci and binary locales are built-in into Manticore. The first one is a generic collation for UTF-8 data (without any so-called language tailoring); it should behave similar to utf8_general_ci collation in MySQL. The second one is a simple bytewise comparison.

Collation can be overridden via SphinxQL on a per-session basis using SET collation_connection statement. All subsequent SphinxQL queries will use this collation. SphinxAPI and SphinxSE queries will use the server default collation, as specified in collation_server configuration directive. Manticore currently defaults to libc_ci collation.

Collations should affect all string attribute comparisons, including those within ORDER BY and GROUP BY, so differently ordered or grouped results can be returned depending on the collation chosen. Note that collations don’t affect full-text searching, for that use charset_table.

Query cache

Query cache stores a compressed result set in memory, and then reuses it for subsequent queries where possible. You can configure it using the following directives:

  • qcache_max_bytes, a limit on the RAM use for cached queries storage. Defaults to 16 MB. Setting qcache_max_bytes to 0 completely disables the query cache.
  • qcache_thresh_msec, the minimum wall query time to cache. Queries that completed faster than this will not be cached. Defaults to 3000 msec, or 3 seconds.
  • qcache_ttl_sec, cached entry TTL, or time to live. Queries will stay cached for this much. Defaults to 60 seconds, or 1 minute.

These settings can be changed on the fly using the SET GLOBAL statement:

mysql> SET GLOBAL qcache_max_bytes=128000000;

These changes are applied immediately, and the cached result sets that no longer satisfy the constraints are immediately discarded. When reducing the cache size on the fly, MRU (most recently used) result sets win.

Query cache works as follows. When it’s enabled, every full-text search result gets completely stored in memory. That happens after full-text matching, filtering, and ranking, so basically we store total_found {docid,weight} pairs. Compressed matches can consume anywhere from 2 bytes to 12 bytes per match on average, mostly depending on the deltas between the subsequent docids. Once the query completes, we check the wall time and size thresholds, and either save that compressed result set for reuse, or discard it.

Note how the query cache impact on RAM is thus not limited by qcache_max_bytes! If you run, say, 10 concurrent queries, each of them matching upto 1M matches (after filters), then the peak temporary RAM use will be in the 40 MB to 240 MB range, even if in the end the queries are quick enough and do not get cached.

Queries can then use cache when the index, the full-text query (ie. MATCH() contents), and the ranker are all a match, and filters are compatible. Meaning:

  • The full-text part within MATCH() must be a bytewise match. Add a single extra space, and that is now a different query where the query cache is concerned.
  • The ranker (and its parameters if any, for user-defined rankers) must be a bytewise match.
  • The filters must be a superset of the original filters. That is, you can add extra filters and still hit the cache. (In this case, the extra filters will be applied to the cached result.) But if you remove one, that will be a new query again.

Cache entries expire with TTL, and also get invalidated on index rotation, or on TRUNCATE, or on ATTACH. Note that at the moment entries are not invalidated on arbitrary RT index writes! So a cached query might be returning older results for the duration of its TTL.

Current cache status can be inspected with in SHOW STATUS through the qcache_XXX variables:

mysql> SHOW STATUS LIKE 'qcache%';
+-----------------------+----------+
| Counter               | Value    |
+-----------------------+----------+
| qcache_max_bytes      | 16777216 |
| qcache_thresh_msec    | 3000     |
| qcache_ttl_sec        | 60       |
| qcache_cached_queries | 0        |
| qcache_used_bytes     | 0        |
| qcache_hits           | 0        |
+-----------------------+----------+
6 rows in set (0.00 sec)

MySQL storage engine (SphinxSE)

SphinxSE overview

SphinxSE is MySQL storage engine which can be compiled into MySQL server 5.x using its pluggable architecture. It is not available for MySQL 4.x series. It also requires MySQL 5.0.22 or higher in 5.0.x series, or MySQL 5.1.12 or higher in 5.1.x series.

Despite the name, SphinxSE does not actually store any data itself. It is actually a built-in client which allows MySQL server to talk to searchd, run search queries, and obtain search results. All indexing and searching happen outside MySQL.

Obvious SphinxSE applications include:

  • easier porting of MySQL FTS applications to Manticore;
  • allowing Manticore use with programming languages for which native APIs are not available yet;
  • optimizations when additional Manticore result set processing on MySQL side is required (eg. JOINs with original document tables, additional MySQL-side filtering, etc).
Installing SphinxSE

You will need to obtain a copy of MySQL sources, prepare those, and then recompile MySQL binary. MySQL sources (mysql-5.x.yy.tar.gz) could be obtained from http://dev.mysql.com Web site.

For some MySQL versions, there are delta tarballs with already prepared source versions available from Manticore Web site. After unzipping those over original sources MySQL would be ready to be configured and built with Manticore support.

If such tarball is not available, or does not work for you for any reason, you would have to prepare sources manually. You will need to GNU Autotools framework (autoconf, automake and libtool) installed to do that.

Compiling MySQL 5.0.x with SphinxSE
  1. copy sphinx.5.0.yy.diff patch file into MySQL sources directory and run
$ patch -p1 < sphinx.5.0.yy.diff
If there’s no .diff file exactly for the specific version you need to
build, try applying .diff with closest version numbers. It is important that the patch should apply with no rejects.
  1. in MySQL sources directory, run
$ sh BUILD/autorun.sh
  1. in MySQL sources directory, create sql/sphinx directory in and copy all files in mysqlse directory from Manticore sources there. Example:
$ cp -R /root/builds/sphinx-0.9.7/mysqlse /root/builds/mysql-5.0.24/sql/sphinx
  1. configure MySQL and enable Manticore engine:
$ ./configure --with-sphinx-storage-engine
  1. build and install MySQL:
$ make
$ make install
Compiling MySQL 5.1.x with SphinxSE
  1. in MySQL sources directory, create storage/sphinx directory in and copy all files in mysqlse directory from Manticore sources there. Example:
$ cp -R /root/builds/sphinx-0.9.7/mysqlse /root/builds/mysql-5.1.14/storage/sphinx
  1. in MySQL sources directory, run
$ sh BUILD/autorun.sh
  1. configure MySQL and enable Manticore engine:
$ ./configure --with-plugins=sphinx
  1. build and install MySQL:
$ make
$ make install
Checking SphinxSE installation

To check whether SphinxSE has been successfully compiled into MySQL, launch newly built servers, run mysql client and issue SHOW ENGINES query. You should see a list of all available engines. Manticore should be present and “Support” column should contain “YES”:

mysql> show engines;
+------------+----------+-------------------------------------------------------------+
| Engine     | Support  | Comment                                                     |
+------------+----------+-------------------------------------------------------------+
| MyISAM     | DEFAULT  | Default engine as of MySQL 3.23 with great performance      |
  ...
| SPHINX     | YES      | Manticore storage engine                                       |
  ...
+------------+----------+-------------------------------------------------------------+
13 rows in set (0.00 sec)
Using SphinxSE

To search via SphinxSE, you would need to create special ENGINE=SPHINX “search table”, and then SELECT from it with full text query put into WHERE clause for query column.

Let’s begin with an example create statement and search query:

CREATE TABLE t1
(
    id          INTEGER UNSIGNED NOT NULL,
    weight      INTEGER NOT NULL,
    query       VARCHAR(3072) NOT NULL,
    group_id    INTEGER,
    INDEX(query)
) ENGINE=SPHINX CONNECTION="sphinx://localhost:9312/test";

SELECT * FROM t1 WHERE query='test it;mode=any';

First 3 columns of search table must have a types of INTEGER UNSINGED or BIGINT for the 1st column (document id), INTEGER or BIGINT for the 2nd column (match weight), and VARCHAR or TEXT for the 3rd column (your query), respectively. This mapping is fixed; you can not omit any of these three required columns, or move them around, or change types. Also, query column must be indexed; all the others must be kept unindexed. Columns’ names are ignored so you can use arbitrary ones.

Additional columns must be either INTEGER, TIMESTAMP, BIGINT, VARCHAR, or FLOAT. They will be bound to attributes provided in Manticore result set by name, so their names must match attribute names specified in sphinx.conf. If there’s no such attribute name in Manticore search results, column will have NULL values.

Special “virtual” attributes names can also be bound to SphinxSE columns. _sph_ needs to be used instead of @ for that. For instance, to obtain the values of @groupby, @count, or @distinct virtual attributes, use _sph_groupby, _sph_count or _sph_distinct column names, respectively.

CONNECTION string parameter can be used to specify default searchd host, port and indexes for queries issued using this table. If no connection string is specified in CREATE TABLE, index name “*” (ie. search all indexes) and localhost:9312 are assumed. Connection string syntax is as follows:

CONNECTION="sphinx://HOST:PORT/INDEXNAME"

You can change the default connection string later:

mysql> ALTER TABLE t1 CONNECTION="sphinx://NEWHOST:NEWPORT/NEWINDEXNAME";

You can also override all these parameters per-query.

As seen in example, both query text and search options should be put into WHERE clause on search query column (ie. 3rd column); the options are separated by semicolons; and their names from values by equality sign. Any number of options can be specified. Available options are:

  • query - query text;
  • mode - matching mode. Must be one of “all”, “any”, “phrase”, “boolean”, or “extended”. Default is “all”;
  • sort - match sorting mode. Must be one of “relevance”, “attr_desc”, “attr_asc”, “time_segments”, or “extended”. In all modes besides “relevance” attribute name (or sorting clause for “extended”) is also required after a colon:
... WHERE query='test;sort=attr_asc:group_id';
... WHERE query='test;sort=extended:@weight desc, group_id asc';
  • offset - offset into result set, default is 0;
  • limit - amount of matches to retrieve from result set, default is 20;
  • index - names of the indexes to search:
... WHERE query='test;index=test1;';
... WHERE query='test;index=test1,test2,test3;';
  • minid, maxid - min and max document ID to match;
  • weights - comma-separated list of weights to be assigned to Manticore full-text fields:
... WHERE query='test;weights=1,2,3;';
  • filter, !filter - comma-separated attribute name and a set of values to match:
# only include groups 1, 5 and 19
... WHERE query='test;filter=group_id,1,5,19;';

# exclude groups 3 and 11
... WHERE query='test;!filter=group_id,3,11;';
  • range, !range - comma-separated (integer or bigint) Manticore attribute name, and min and max values to match:
# include groups from 3 to 7, inclusive
... WHERE query='test;range=group_id,3,7;';

# exclude groups from 5 to 25
... WHERE query='test;!range=group_id,5,25;';
  • floatrange, !floatrange - comma-separated (floating point) Manticore attribute name, and min and max values to match:
# filter by a float size
... WHERE query='test;floatrange=size,2,3;';

# pick all results within 1000 meter from geoanchor
... WHERE query='test;floatrange=@geodist,0,1000;';
  • maxmatches - per-query max matches value, as in max_matches parameter to SetLimits() API call:
... WHERE query='test;maxmatches=2000;';
  • cutoff - maximum allowed matches, as in cutoff parameter to SetLimits() API call:
... WHERE query='test;cutoff=10000;';
  • maxquerytime - maximum allowed query time (in milliseconds), as in SetMaxQueryTime() API call:
... WHERE query='test;maxquerytime=1000;';
  • groupby - group-by function and attribute, corresponding to SetGroupBy() API call:
... WHERE query='test;groupby=day:published_ts;';
... WHERE query='test;groupby=attr:group_id;';
  • groupsort - group-by sorting clause:
... WHERE query='test;groupsort=@count desc;';
  • distinct - an attribute to compute COUNT(DISTINCT) for when doing group-by, as in SetGroupDistinct() API call:
... WHERE query='test;groupby=attr:country_id;distinct=site_id';
  • indexweights - comma-separated list of index names and weights to use when searching through several indexes:
... WHERE query='test;indexweights=idx_exact,2,idx_stemmed,1;';
  • fieldweights - comma-separated list of per-field weights that can be used by the ranker:
... WHERE query='test;fieldweights=title,10,abstract,3,content,1;';
  • comment - a string to mark this query in query log (mapping to $comment parameter in Query() API call):
... WHERE query='test;comment=marker001;';
  • select - a string with expressions to compute (mapping to SetSelect() API call):
... WHERE query='test;select=2*a+3*** as myexpr;';
  • host, port - remote searchd host name and TCP port, respectively:
... WHERE query='test;host=sphinx-test.loc;port=7312;';
  • ranker - a ranking function to use with “extended” matching mode, as in SetRankingMode() API call (the only mode that supports full query syntax). Known values are “proximity_bm25”, “bm25”, “none”, “wordcount”, “proximity”, “matchany”, “fieldmask”, “sph04”, “expr:EXPRESSION” syntax to support expression-based ranker (where EXPRESSION should be replaced with your specific ranking formula), and “export:EXPRESSION”:
... WHERE query='test;mode=extended;ranker=bm25;';
... WHERE query='test;mode=extended;ranker=expr:sum(lcs);';
The “export” ranker works exactly like ranker=expr, but it stores the
per-document factor values, while ranker=expr discards them after computing the final WEIGHT() value. Note that ranker=export is meant to be used but rarely, only to train a ML (machine learning) function or to define your own ranking function by hand, and never in actual production. When using this ranker, you’ll probably want to examine the output of the RANKFACTORS() function that produces a string with all the field level factors for each document.
        SELECT *, WEIGHT(), RANKFACTORS()
            FROM myindex
            WHERE MATCH('dog')
            OPTION ranker=export('100*bm25')

would produce something like
*************************** 1\. row ***************************
           id: 555617
    published: 1110067331
   channel_id: 1059819
        title: 7
      content: 428
     weight(): 69900
rankfactors(): bm25=699, bm25a=0.666478, field_mask=2,
doc_word_count=1, field1=(lcs=1, hit_count=4, word_count=1,
tf_idf=1.038127, min_idf=0.259532, max_idf=0.259532, sum_idf=0.259532,
min_hit_pos=120, min_best_span_pos=120, exact_hit=0,
max_window_hits=1), word1=(tf=4, idf=0.259532)
*************************** 2\. row ***************************
           id: 555313
    published: 1108438365
   channel_id: 1058561
        title: 8
      content: 249
     weight(): 68500
rankfactors(): bm25=685, bm25a=0.675213, field_mask=3,
doc_word_count=1, field0=(lcs=1, hit_count=1, word_count=1,
tf_idf=0.259532, min_idf=0.259532, max_idf=0.259532, sum_idf=0.259532,
min_hit_pos=8, min_best_span_pos=8, exact_hit=0, max_window_hits=1),
field1=(lcs=1, hit_count=2, word_count=1, tf_idf=0.519063,
min_idf=0.259532, max_idf=0.259532, sum_idf=0.259532, min_hit_pos=36,
min_best_span_pos=36, exact_hit=0, max_window_hits=1), word1=(tf=3,
idf=0.259532)
  • geoanchor - geodistance anchor, as in SetGeoAnchor() API call. Takes 4 parameters which are latitude and longitude attribute names, and anchor point coordinates respectively:
... WHERE query='test;geoanchor=latattr,lonattr,0.123,0.456';

One very important note that it is much more efficient to allow Manticore to perform sorting, filtering and slicing the result set than to raise max matches count and use WHERE, ORDER BY and LIMIT clauses on MySQL side. This is for two reasons. First, Manticore does a number of optimizations and performs better than MySQL on these tasks. Second, less data would need to be packed by searchd, transferred and unpacked by SphinxSE.

Additional query info besides result set could be retrieved with SHOW ENGINE SPHINX STATUS statement:

mysql> SHOW ENGINE SPHINX STATUS;
+--------+-------+-------------------------------------------------+
| Type   | Name  | Status                                          |
+--------+-------+-------------------------------------------------+
| SPHINX | stats | total: 25, total found: 25, time: 126, words: 2 |
| SPHINX | words | sphinx:591:1256 soft:11076:15945                |
+--------+-------+-------------------------------------------------+
2 rows in set (0.00 sec)

This information can also be accessed through status variables. Note that this method does not require super-user privileges.

mysql> SHOW STATUS LIKE 'sphinx_%';
+--------------------+----------------------------------+
| Variable_name      | Value                            |
+--------------------+----------------------------------+
| sphinx_total       | 25                               |
| sphinx_total_found | 25                               |
| sphinx_time        | 126                              |
| sphinx_word_count  | 2                                |
| sphinx_words       | sphinx:591:1256 soft:11076:15945 |
+--------------------+----------------------------------+
5 rows in set (0.00 sec)

You could perform JOINs on SphinxSE search table and tables using other engines. Here’s an example with “documents” from example.sql:

mysql> SELECT content, date_added FROM test.documents docs
-> JOIN t1 ON (docs.id=t1.id)
-> WHERE query="one document;mode=any";
+-------------------------------------+---------------------+
| content                             | docdate             |
+-------------------------------------+---------------------+
| this is my test document number two | 2006-06-17 14:04:28 |
| this is my test document number one | 2006-06-17 14:04:28 |
+-------------------------------------+---------------------+
2 rows in set (0.00 sec)

mysql> SHOW ENGINE SPHINX STATUS;
+--------+-------+---------------------------------------------+
| Type   | Name  | Status                                      |
+--------+-------+---------------------------------------------+
| SPHINX | stats | total: 2, total found: 2, time: 0, words: 2 |
| SPHINX | words | one:1:2 document:2:2                        |
+--------+-------+---------------------------------------------+
2 rows in set (0.00 sec)

Building snippets (excerpts) via MySQL

SphinxSE also includes a UDF function that lets you create snippets through MySQL. The functionality is fully similar to BuildExcerprts API call but accessible through MySQL+SphinxSE.

The binary that provides the UDF is named sphinx.so and should be automatically built and installed to proper location along with SphinxSE itself. If it does not get installed automatically for some reason, look for sphinx.so in the build directory and copy it to the plugins directory of your MySQL instance. After that, register the UDF using the following statement:

CREATE FUNCTION sphinx_snippets RETURNS STRING SONAME 'sphinx.so';

Function name must be sphinx_snippets, you can not use an arbitrary name. Function arguments are as follows:

Prototype: function sphinx_snippets ( document, index, words, [options] );

Document and words arguments can be either strings or table columns. Options must be specified like this: &#039;value&#039; AS option_name. For a list of supported options, refer to BuildExcerprts() API call. The only UDF-specific additional option is named &#039;sphinx&#039; and lets you specify searchd location (host and port).

Usage examples:

SELECT sphinx_snippets('hello world doc', 'main', 'world',
    'sphinx://192.168.1.1/' AS sphinx, true AS exact_phrase,
    '[**]' AS before_match, '[/**]' AS after_match)
FROM documents;

SELECT title, sphinx_snippets(text, 'index', 'mysql php') AS text
    FROM sphinx, documents
    WHERE query='mysql php' AND sphinx.id=documents.id;

Percolate query

Note

This is a new feature, not production ready yet, just for testing purposes mostly for now. Changes will occur in future updates.

The percolate query is used to match documents against queries stored in a index. It is also called “search in reverse” as it works opposite to a regular search where documents are stored in an index and queries are issued against the index.

Queries are stored in a special RealTime index and they can be added, deleted and listed using INSERT/DELETE/SELECT statements similar way as it’s done for a regular index.

Checking if a document matches any of the predefined criterias (queries) can be done with the CALL PQ function, which returns a list of the matched queries. Note that it does not add documents to the percolate index. You need to use another index (regular or RealTime) in which you will insert documents to perform regular searches.

Tags

A percolate query can have tags. tags can be set for the query with INSERT statement. Later on a user might list queries with specific tags with SELECT statement or delete query(es) with DELETE statement.

Filters

A percolate query can have filters. filters are set for the query with INSERT statement. Documents can be then filtered according to the filters with CALL PQ statement.

Index

A percolate query works only for percolate index type. Its configuration is similar to Real-time index, however the declaration of fields and attributes can be omitted, in this case the index is created with default field text and attribute gid.

index pq
{
    type = percolate
    path = path/index_name
    min_infix_len   = 4
}

INSERT

To store a query the INSERT statement looks like

INSERT INTO index_name (query, tags, filters) VALUES ( 'full text query terms', 'tags', 'filters' );
INSERT INTO index_name (query) VALUES ( 'full text query terms');
INSERT INTO index_name VALUES ( 'full text query terms', 'tags');
INSERT INTO index_name VALUES ( 'full text query terms');

where tags and filters are optional fields. In case no schema declared for the INSERT statement te first field will be full-text query and the optional second field will be tags. filters is a string and has the same format as SphinxQL WHERE clause.

CALL PQ

To search for queries matching a document(s) the CALL PQ statement is used which looks like

CALL PQ ('index_name', 'single document', 0 as docs, 0 as docs_json, 0 as verbose);
CALL PQ ('index_name', ('multiple documents', 'go this way'), 0 as docs_json );

The document in CALL PQ can be JSON encoded string or raw string. Fields and attributes mapping are allowed for JSON documents only.

CALL PQ ('pq', (
'{"title":"header text", "body":"post context", "timestamp":11 }',
'{"title":"short post", "counter":7 }'
) );

CALL PQ can have multiple options set as option_name.

Here are default values for the options:

  • docs_json - 1 (enabled), to treat document(s) as JSON encoded string or raw string otherwise
  • docs - 0 (disabled), to provide per query documents matched at result set
  • verbose - 0 (disabled), to provide extended info on matching at SHOW META
  • query - 0 (disabled), to provide all query fields stored, such as query, tags, filters

List stored queries

To list stored queries in index the SELECT statement looks like

SELECT * FROM index_name;
SELECT * FROM index_name WHERE tags='tags list';
SELECT * FROM index_name WHERE uid IN (11,35,101);

In case tags provided matching queries will be shown if any tags from the SELECT statement match tags in the stored query. In case uid provided range or value list filter will be used to filter out stored queries.

The SELECT supports count(*) and count(*) alias to get number of of percolate queries. Any values are just ignored there however count(*) should provide the total amount of queries stored.

mysql> select count(*) c from pq;
+------+
| c    |
+------+
|    3 |
+------+

Delete query

To delete a stored percolate query(es) in index the DELETE statement looks like

DELETE FROM index_name WHERE id=1;
DELETE FROM index_name WHERE tags='tags list';

In case tags provided the query will be deleted if any tags from the DELETE statement match any of its tags.

To delete all stored query(es) in index there is TRUNCATE statement looks like

TRUNCATE RTINDEX index_name;

Meta

Meta information is kept for documents on “CALL PQ” and can be retrieved with SHOW META call.

SHOW META output after CALL PQ looks like

+-------------------------+-----------+
| Name                    | Value     |
+-------------------------+-----------+
| Total                   | 0.010 sec |
| Queries matched         | 950       |
| Document matches        | 1500      |
| Total queries stored    | 1000      |
| Term only queries       | 998       |
+-------------------------+-----------+

With entries:

  • Total - total time spent for matching the document(s)
  • Queries matched - how many stored queries match the document(s)
  • Document matches - how many times the documents match the queries stored in the index
  • Total queries stored - how many queries are stored in the index at all
  • Term only queries - how many queries in the index have terms. The rest of the queries have extended query syntax

Reconfigure

As well as for RealTime indexes ALTER RECONFIGURE command is also supported for percolate query index. It allows to reconfigure percolate index on the fly without deleting and repopulating the index with queries back.

mysql> desc pq1;
+-------+--------+
| Field | Type   |
+-------+--------+
| id    | bigint |
| text  | field  |
| body  | field  |
| k     | uint   |
+-------+--------+

mysql> select * from pq1;
+------+-------+------+-------------+
| UID  | Query | Tags | Filters     |
+------+-------+------+-------------+
|    1 | test  |      |  k=4        |
|    2 | test  |      |  k IN (4,6) |
|    3 | test  |      |             |
+------+-------+------+-------------+

Add JSON attribute to the index config rt_attr_json = json_data, then issue ALTER RECONFIGURE

mysql> desc pq1;
+-----------+--------+
| Field     | Type   |
+-----------+--------+
| id        | bigint |
| text      | field  |
| body      | field  |
| k         | uint   |
| json_data | json   |
+-----------+--------+

Extending

UDFs (User Defined Functions)

Our expression engine can be extended with user defined functions, or UDFs for short, like this:

SELECT id, attr1, myudf(attr2, attr3+attr4) ...

You can load and unload UDFs dynamically into searchd without having to restart the daemon, and used them in expressions when searching, ranking, etc. Quick summary of the UDF features is as follows.

  • UDFs can take integer (both 32-bit and 64-bit), float, string, MVA, or PACKEDFACTORS() arguments.
  • UDFs can return integer, float, or string values.
  • UDFs can check the argument number, types, and names during the query setup phase, and raise errors.
  • Aggregation UDFs are not yet supported (but might be in the future).

UDFs have a wide variety of uses, for instance:

  • adding custom mathematical or string functions;
  • accessing the database or files from within Manticore;
  • implementing complex ranking functions.

UDFs reside in the external dynamic libraries (.so files on UNIX and .dll on Windows systems). Library files need to reside in a trusted folder specified by plugin_dir directive, for obvious security reasons: securing a single folder is easy; letting anyone install arbitrary code into searchd is a risk. You can load and unload them dynamically into searchd with CREATE FUNCTION and DROP FUNCTION SphinxQL statements respectively. Also, you can seamlessly reload UDFs (and other plugins) with RELOAD PLUGINS statement. Manticore keeps track of the currently loaded functions, that is, every time you create or drop an UDF, searchd writes its state to the sphinxql_state file as a plain good old SQL script.

Once you successfully load an UDF, you can use it in your SELECT or other statements just as well as any of the builtin functions:

SELECT id, MYCUSTOMFUNC(groupid, authorname), ... FROM myindex

Multiple UDFs (and other plugins) may reside in a single library. That library will only be loaded once. It gets automatically unloaded once all the UDFs and plugins from it are dropped.

In theory you can write an UDF in any language as long as its compiler is able to import standard C header, and emit standard dynamic libraries with properly exported functions. Of course, the path of least resistance is to write in either C++ or plain C. We provide an example UDF library written in plain C and implementing several functions (demonstrating a few different techniques) along with our source code, see src/udfexample.c. That example includes src/sphinxudf.h header file definitions of a few UDF related structures and types. For most UDFs and plugins, a mere #include "sphinxudf.h", like in the example, should be completely sufficient, too. However, if you’re writing a ranking function and need to access the ranking signals (factors) data from within the UDF, you will also need to compile and link with src/sphinxudf.c (also available in our source code), because the implementations of the fuctions that let you access the signal data from within the UDF reside in that file.

Both sphinxudf.h header and sphinxudf.c are standalone. So you can copy around those files only; they do not depend on any other bits of Manticore source code.

Within your UDF, you must implement and export only a couple functions, literally. First, for UDF interface version control, you must define a function int LIBRARYNAME_ver(), where LIBRARYNAME is the name of your library file, and you must return SPH_UDF_VERSION (a value defined in sphinxudf.h) from it. Here’s an example.

#include <sphinxudf.h>

// our library will be called udfexample.so, thus, so it must define
// a version function named udfexample_ver()
int udfexample_ver()
{
    return SPH_UDF_VERSION;
}

That protects you from accidentally loading a library with a mismatching UDF interface version into a newer or older searchd. Second, yout must implement the actual function, too. sphinx_int64_t testfunc ( SPH_UDF_INIT * init, SPH_UDF_ARGS * args, char * error_flag ) { return 123; }

UDF function names in SphinxQL are case insensitive. However, the respective C function names are not, they need to be all lower-case, or the UDF will not load. More importantly, it is vital that a) the calling convention is C (aka __cdecl), b) arguments list matches the plugin system expectations exactly, and c) the return type matches the one you specify in CREATE FUNCTION. Unfortunately, there is no (easy) way for us to check for those mistakes when loading the function, and they could crash the server and/or result in unexpected results. Last but not least, all the C functions you implement need to be thread-safe.

The first argument, a pointer to SPH_UDF_INIT structure, is essentially a pointer to our function state. It is option. In the example just above the function is stateless, it simply returns 123 every time it gets called. So we do not have to define an initialization function, and we can simply ignore that argument.

The second argument, a pointer to SPH_UDF_ARGS, is the most important one. All the actual call arguments are passed to your UDF via this structure; it contians the call argument count, names, types, etc. So whether your function gets called like SELECT id, testfunc(1) or like SELECT id, testfunc(&#039;abc&#039;, 1000*id+gid, WEIGHT()) or anyhow else, it will receive the very same SPH_UDF_ARGS structure in all of these cases. However, the data passed in the args structure will be different. In the first example args->arg_count will be set to 1, in the second example it will be set to 3, args->arg_types array will contain different type data, and so on.

Finally, the third argument is an error flag. UDF can raise it to indicate that some kinda of an internal error happened, the UDF can not continue, and the query should terminate early. You should not use this for argument type checks or for any other error reporting that is likely to happen during normal use. This flag is designed to report sudden critical runtime errors, such as running out of memory.

If we wanted to, say, allocate temporary storage for our function to use, or check upfront whether the arguments are of the supported types, then we would need to add two more functions, with UDF initialization and deinitialization, respectively.

int testfunc_init ( SPH_UDF_INIT * init, SPH_UDF_ARGS * args,
    char * error_message )
{
    // allocate and initialize a little bit of temporary storage
    init->func_data = malloc ( sizeof(int) );
    *(int*)init->func_data = 123;

    // return a success code
    return 0;
}

void testfunc_deinit ( SPH_UDF_INIT * init )
{
    // free up our temporary storage
    free ( init->func_data );
}

Note how testfunc_init() also receives the call arguments structure. By the time it is called it does not receive any actual values, so the args->arg_values will be NULL. But the argument names and types are known and will be passed. You can check them in the initialization function and return an error if they are of an unsupported type.

UDFs can receive arguments of pretty much any valid internal Manticore type. Refer to sphinx_udf_argtype enumeration in sphinxudf.h for a full list. Most of the types map straightforwardly to the respective C types. The most notable exception is the SPH_UDF_TYPE_FACTORS argument type. You get that type by calling your UDF with a PACKEDFACTOR() argument. It’s data is a binary blob in a certain internal format, and to extract individual ranking signals from that blob, you need to use either of the two sphinx_factors_XXX() or sphinx_get_YYY_factor() families of functions. The first family consists of just 3 functions, sphinx_factors_init() that initializes the unpacked SPH_UDF_FACTORS structure, sphinx_factors_unpack() that unpacks a binary blob into it, and sphinx_factors_deinit() that cleans up an deallocates the SPH_UDF_FACTORS. So you need to call init() and unpack(), then you can use the SPH_UDF_FACTORS fields, and then you need to cleanup with deinit(). That is simple, but results in a bunch of memory allocations per each processed document, and might be slow. The other interface, consisting of a bunch of sphinx_get_YYY_factor() functions, is a little more wordy to use, but accesses the blob data directly and guarantees that there will be zero allocations. So for top-notch ranking UDF performance, you want to use that one.

As for the return types, UDFs can currently return a signle INTEGER, BIGINT, FLOAT, or STRING value. The C function return type should be sphinx_int64_t, sphinx_int64_t, double, or char* respectively. In the last case you must use args->fn_malloc function to allocate the returned string values. Internally in your UDF you can use whatever you want, so the testfunc_init() example above is correct code even though it uses malloc() directly: you manage that pointer yourself, it gets freed up using a matching free() call, and all is well. However, the returned strings values are managed by Manticore and we have our own allocator, so for the return values specifically, you need to use it too.

Depending on how your UDFs are used in the query, the main function call (testfunc() in our example) might be called in a rather different volume and order. Specifically,

  • UDFs referenced in WHERE, ORDER BY, or GROUP BY clauses must and will be evaluated for every matched document. They will be called in the natural matching order.
  • without subselects, UDFs that can be evaluated at the very last stage over the final result set will be evaluated that way, but before applying the LIMIT clause. They will be called in the result set order.
  • with subselects, such UDFs will also be evaluated after applying the inner LIMIT clause.

The calling sequence of the other functions is fixed, though. Namely,

  • testfunc_init() is called once when initializing the query. It can return a non-zero code to indicate a failure; in that case query will be terminated, and the error message from the error_message buffer will be returned.
  • testfunc() is called for every eligible row (see above), whenever Manticore needs to compute the UDF value. It can also indicate an (internal) failure error by writing a non-zero byte value to error_flag. In that case, it is guaranteed that will no more be called for subsequent rows, and a default return value of 0 will be substituted. Manticore might or might not choose to terminate such queries early, neither behavior is currently guaranteed.
  • testfunc_deinit() is called once when the query processing (in a given index shard) ends.

We do not yet support aggregation functions. In other words, your UDFs will be called for just a single document at a time and are expected to return some value for that document. Writing a function that can compute an aggregate value like AVG() over the entire group of documents that share the same GROUP BY key is not yet possible. However, you can use UDFs within the builtin aggregate functions: that is, even though MYCUSTOMAVG() is not supported yet, AVG(MYCUSTOMFUNC()) should work alright!

UDFs are local. In order to use them on a cluster, you have to put the same library on all its nodes and run CREATEs on all the nodes too. This might change in the future versions.

Plugins

Here’s the complete plugin type list.

  • UDF plugins;
  • ranker plugins;
  • indexing-time token filter plugins;
  • query-time token filter plugins.

This section discusses writing and managing plugins in general; things specific to writing this or that type of a plugin are then discussed in their respective subsections.

So, how do you write and use a plugin? Four-line crash course goes as follows:

  • create a dynamic library (either .so or.dll), most likely in C or C++;
  • load that plugin into searchd using CREATE PLUGIN;
  • invoke it using the plugin specific calls (typically using this or that OPTION).
  • to unload or reload a plugin use DROP PLUGIN and RELOAD PLUGINS respectively.

Note that while UDFs are first-class plugins they are nevertheless installed using a separate CREATE FUNCTION statement. It lets you specify the return type neatly so there was especially little reason to ruin backwards compatibility and change the syntax.

Dynamic plugins are supported in workers = threads <workers> and workers = thread_pool <workers> mode only. Multiple plugins (and/or UDFs) may reside in a single library file. So you might choose to either put all your project-specific plugins in a single common uber-library; or you might choose to have a separate library for every UDF and plugin; that is up to you.

Just as with UDFs, you want to include src/sphinxudf.h header file. At the very least, you will need the SPH_UDF_VERSION constant to implement a proper version function. Depending on the specific plugin type, you might or might not need to link your plugin with src/sphinxudf.c. However, all the functions implemented in sphinxudf.c are about unpacking the PACKEDFACTORS() blob, and no plugin types are exposed to that kind of data. So currently, you would never need to link with the C-file, just the header would be sufficient. (In fact, if you copy over the UDF version number, then for some of the plugin types you would not even need the header file.)

Formally, plugins are just sets of C functions that follow a certain naming parttern. You are typically required to define just one key function that does the most important work, but you may define a bunch of other functions, too. For example, to implement a ranker called “myrank”, you must define myrank_finalize() function that actually returns the rank value, however, you might also define myrank_init(), myrank_update(), and myrank_deinit() functions. Specific sets of well-known suffixes and the call arguments do differ based on the plugin type, but _init() and _deinit() are generic, every plugin has those. Protip: for a quick reference on the known suffixes and their argument types, refer to sphinxplugin.h, we define the call prototoypes in the very beginning of that file.

Despite having the public interface defined in ye good olde good pure C, our plugins essentially follow the object-oriented model. Indeed, every _init() function receives a void ** userdata out-parameter. And the pointer value that you store at (*userdata) location is then be passed as a 1st argument to all the other plugin functions. So you can think of a plugin as class that gets instantiated every time an object of that class is needed to handle a request: the userdata pointer would be its this pointer; the functions would be its methods, and the _init() and _deinit() functions would be the constructor and destructor respectively.

Why this (minor) OOP-in-C complication? Well, plugins run in a multi-threaded environment, and some of them have to be stateful. You can’t keep that state in a global variable in your plugin. So we have to pass around a userdata parameter anyway to let you keep that state. And that naturally brings us to the OOP model. And if you’ve got a simple, stateless plugin, the interface lets you omit the _init() and _deinit() and whatever other functions just as well.

To summarize, here goes the simplest complete ranker plugin, in just 3 lines of C code.

// gcc -fPIC -shared -o myrank.so myrank.c
#include "sphinxudf.h"
int myrank_ver() { return SPH_UDF_VERSION; }
int myrank_finalize(void *u, int w) { return 123; }

And this is how you use it:

mysql> CREATE PLUGIN myrank TYPE 'ranker' SONAME 'myrank.dll';
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT id, weight() FROM test1 WHERE MATCH('test')
    -> OPTION ranker=myrank('');
+------+----------+
| id   | weight() |
+------+----------+
|    1 |      123 |
|    2 |      123 |
+------+----------+
2 rows in set (0.01 sec)

Ranker plugins

Ranker plugins let you implement a custom ranker that receives all the occurrences of the keywords matched in the document, and computes a WEIGHT() value. They can be called as follows:

SELECT id, attr1 FROM test WHERE match('hello')
OPTION ranker=myranker('option1=1');

The call workflow is as follows:

  1. XXX_init() gets called once per query per index, in the very beginning. A few query-wide options are passed to it through a SPH_RANKER_INIT structure, including the user options strings (in the example just above, “option1=1” is that string).
  2. XXX_update() gets called multiple times per matched document, with every matched keyword occurrence passed as its parameter, a SPH_RANKER_HIT structure. The occurrences within each document are guaranteed to be passed in the order of ascending hit->hit_pos values.
  3. XXX_finalize() gets called once per matched document, once there are no more keyword occurrences. It must return the WEIGHT() value. This is the only mandatory function.
  4. XXX_deinit() gets called once per query, in the very end.

Command line tools reference

As mentioned elsewhere, Manticore is not a single program called ‘sphinx’, but a collection of 4 separate programs which collectively form Manticore. This section covers these tools and how to use them.

indexer command reference

indexer is the first of the two principal tools as part of Manticore. Invoked from either the command line directly, or as part of a larger script, indexer is solely responsible for gathering the data that will be searchable.

The calling syntax for indexer is as follows:

indexer [OPTIONS] [indexname1 [indexname2 [...]]]

Essentially you would list the different possible indexes (that you would later make available to search) in sphinx.conf, so when calling indexer, as a minimum you need to be telling it what index (or indexes) you want to index.

If sphinx.conf contained details on 2 indexes, mybigindex and mysmallindex, you could do the following:

$ indexer mybigindex
$ indexer mysmallindex mybigindex

As part of the configuration file, sphinx.conf, you specify one or more indexes for your data. You might call indexer to reindex one of them, ad-hoc, or you can tell it to process all indexes - you are not limited to calling just one, or all at once, you can always pick some combination of the available indexes.

The exit codes are as follows:

  • 0, everything went ok
  • 1, there was a problem while indexing (and if –rotate was specified, it was skipped)
  • 2, indexing went ok, but –rotate attempt failed

The majority of the options for indexer are given in the configuration file, however there are some options you might need to specify on the command line as well, as they can affect how the indexing operation is performed. These options are:

  • --config <file> (-c <file> for short) tells indexer to use the given file as its configuration. Normally, it will look for sphinx.conf in the installation directory (e.g. /usr/local/sphinx/etc/sphinx.conf if installed into /usr/local/sphinx), followed by the current directory you are in when calling indexer from the shell. This is most of use in shared environments where the binary files are installed somewhere like /usr/local/sphinx/ but you want to provide users with the ability to make their own custom Manticore set-ups, or if you want to run multiple instances on a single server. In cases like those you could allow them to create their own sphinx.conf files and pass them to indexer with this option. For example:

    $ indexer --config /home/myuser/sphinx.conf myindex
    
  • --all tells indexer to update every index listed in sphinx.conf, instead of listing individual indexes. This would be useful in small configurations, or cron-type or maintenance jobs where the entire index set will get rebuilt each day, or week, or whatever period is best. Example usage:

    $ indexer --config /home/myuser/sphinx.conf --all
    
  • --rotate is used for rotating indexes. Unless you have the situation where you can take the search function offline without troubling users, you will almost certainly need to keep search running whilst indexing new documents. --rotate creates a second index, parallel to the first (in the same place, simply including .new in the filenames). Once complete, indexer notifies searchd via sending the SIGHUP signal, and searchd will attempt to rename the indexes (renaming the existing ones to include .old and renaming the .new to replace them), and then start serving from the newer files. Depending on the setting of seamless_rotate, there may be a slight delay in being able to search the newer indexes. Example usage:

    $ indexer --rotate --all
    
  • --quiet tells indexer not to output anything, unless there is an error. Again, most used for cron-type, or other script jobs where the output is irrelevant or unnecessary, except in the event of some kind of error. Example usage:

    $ indexer --rotate --all --quiet
    
  • --noprogress does not display progress details as they occur; instead, the final status details (such as documents indexed, speed of indexing and so on are only reported at completion of indexing. In instances where the script is not being run on a console (or ‘tty’), this will be on by default. Example usage:

    $ indexer --rotate --all --noprogress
    
  • --buildstops <outputfile.text> <N> reviews the index source, as if it were indexing the data, and produces a list of the terms that are being indexed. In other words, it produces a list of all the searchable terms that are becoming part of the index. Note; it does not update the index in question, it simply processes the data ‘as if’ it were indexing, including running queries defined with sql_query_pre or sql_query_post. outputfile.txt will contain the list of words, one per line, sorted by frequency with most frequent first, and N specifies the maximum number of words that will be listed; if sufficiently large to encompass every word in the index, only that many words will be returned. Such a dictionary list could be used for client application features around “Did you mean…” functionality, usually in conjunction with --buildfreqs, below. Example:

    $ indexer myindex --buildstops word_freq.txt 1000
    

    This would produce a document in the current directory, word_freq.txt with the 1,000 most common words in ‘myindex’, ordered by most common first. Note that the file will pertain to the last index indexed when specified with multiple indexes or --all (i.e. the last one listed in the configuration file)

  • --buildfreqs works with --buildstops (and is ignored if --buildstops is not specified). As --buildstops provides the list of words used within the index, --buildfreqs adds the quantity present in the index, which would be useful in establishing whether certain words should be considered stopwords if they are too prevalent. It will also help with developing “Did you mean…” features where you can how much more common a given word compared to another, similar one. Example:

    $ indexer myindex --buildstops word_freq.txt 1000 --buildfreqs
    

    This would produce the word_freq.txt as above, however after each word would be the number of times it occurred in the index in question.

  • --merge <dst-index> <src-index> is used for physically merging indexes together, for example if you have a main+delta scheme, where the main index rarely changes, but the delta index is rebuilt frequently, and --merge would be used to combine the two. The operation moves from right to left - the contents of src-index get examined and physically combined with the contents of dst-index and the result is left in dst-index. In pseudo-code, it might be expressed as: dst-index += src-index An example:

    $ indexer --merge main delta --rotate
    

    In the above example, where the main is the master, rarely modified index, and delta is the less frequently modified one, you might use the above to call indexer to combine the contents of the delta into the main index and rotate the indexes.

  • --merge-dst-range <attr> <min> <max> runs the filter range given upon merging. Specifically, as the merge is applied to the destination index (as part of --merge, and is ignored if --merge is not specified), indexer will also filter the documents ending up in the destination index, and only documents will pass through the filter given will end up in the final index. This could be used for example, in an index where there is a ‘deleted’ attribute, where 0 means ‘not deleted’. Such an index could be merged with:

    $ indexer --merge main delta --merge-dst-range deleted 0 0
    

    Any documents marked as deleted (value 1) would be removed from the newly-merged destination index. It can be added several times to the command line, to add successive filters to the merge, all of which must be met in order for a document to become part of the final index.

  • --merge-killlists (and its shorter alias --merge-klists) changes the way kill lists are processed when merging indexes. By default, both kill lists get discarded after a merge. That supports the most typical main+delta merge scenario. With this option enabled, however, kill lists from both indexes get concatenated and stored into the destination index. Note that a source (delta) index kill list will be used to suppress rows from a destination (main) index at all times.

  • --keep-attrs allows to reuse existing attributes on reindexing. Whenever the index is rebuilt, each new document id is checked for presence in the “old” index, and if it already exists, its attributes are transferred to the “new” index; if not found, attributes from the new index are used. If the user has updated attributes in the index, but not in the actual source used for the index, all updates will be lost when reindexing; using –keep-attrs enables saving the updated attribute values from the previous index. It is possible to specify a path for index files to used instead of reference path from config:

    indexer myindex --keep-attrs=/path/to/index/files
    
  • --keep-attrs-names=<attributes list> allows to specify attributes to reuse from existing index on reindexing. By default all attributes from existed index reused at new “index”

    indexer myindex --keep-attrs=/path/to/index/files --keep-attrs-names=update,state
    
  • --dump-rows <FILE> dumps rows fetched by SQL source(s) into the specified file, in a MySQL compatible syntax. Resulting dumps are the exact representation of data as received by indexer and help to repeat indexing-time issues.

  • --verbose guarantees that every row that caused problems indexing (duplicate, zero, or missing document ID; or file field IO issues; etc) will be reported. By default, this option is off, and problem summaries may be reported instead.

  • --sighup-each is useful when you are rebuilding many big indexes, and want each one rotated into searchd as soon as possible. With --sighup-each, indexer will send a SIGHUP signal to searchd after successfully completing the work on each index. (The default behavior is to send a single SIGHUP after all the indexes were built.)

  • --nohup is useful when you want to check your index with indextool before actually rotating it. indexer won’t send SIGHUP if this option is on.

  • --print-queries prints out SQL queries that indexer sends to the database, along with SQL connection and disconnection events. That is useful to diagnose and fix problems with SQL sources.

indextool command reference

indextool is one of the helper tools within the Manticore package. It is used to dump miscellaneous debug information about the physical index. (Additional functionality such as index verification is planned in the future, hence the indextool name rather than just indexdump.) Its general usage is:

indextool <command> [options]

Options apply to all commands:

  • --config <file> (-c <file> for short) overrides the built-in config file names.
  • --quiet (-q for short) keep indextool quiet - it will not output banner, etc.

The commands are as follows:

  • --checkconfig just loads and verifies the config file to check if it’s valid, without syntax errors.
  • --build-infixes INDEXNAME build infixes for an existing dict=keywords index (upgrades .sph, .spi in place). You can use this option for legacy index files that already use dict=keywords, but now need to support infix searching too; updating the index files with indextool may prove easier or faster than regenerating them from scratch with indexer.
  • --dumpheader FILENAME.sph quickly dumps the provided index header file without touching any other index files or even the configuration file. The report provides a breakdown of all the index settings, in particular the entire attribute and field list.
  • --dumpconfig FILENAME.sph dumps the index definition from the given index header file in (almost) compliant sphinx.conf file format.
  • --dumpheader INDEXNAME dumps index header by index name with looking up the header path in the configuration file.
  • --dumpdict INDEXNAME dumps dictionary.
  • --dumpdocids INDEXNAME dumps document IDs by index name. It takes the data from attribute (.spa) file and therefore requires docinfo=extern to work.
  • --dumphitlist INDEXNAME KEYWORD dumps all the hits (occurrences) of a given keyword in a given index, with keyword specified as text.
  • --dumphitlist INDEXNAME --wordid ID dumps all the hits (occurrences) of a given keyword in a given index, with keyword specified as internal numeric ID.
  • --fold INDEXNAME OPTFILE This options is useful too see how actually tokenizer proceeds input. You can feed indextool with text from file if specified or from stdin otherwise. The output will contain spaces instead of separators (accordingly to your charset_table settings) and lowercased letters in words.
  • --html_strip INDEXNAME filters stdin using HTML stripper settings for a given index, and prints the filtering results to stdout. Note that the settings will be taken from sphinx.conf, and not the index header.
  • --morph INDEXNAME applies morphology to the given stdin and prints the result to stdout.
  • --check INDEXNAME checks the index data files for consistency errors that might be introduced either by bugs in indexer and/or hardware faults. --check also works on RT indexes, RAM and disk chunks.
  • --strip-path strips the path names from all the file names referenced from the index (stopwords, wordforms, exceptions, etc). This is useful for checking indexes built on another machine with possibly different path layouts.
  • --optimize-rt-klists optimizes the kill list memory use in the disk chunk of a given RT index. That is a one-off optimization intended for rather old RT indexes. In last releases this kill list optimization (purging) should happen automatically, and there should never be a need to use this option.
  • --rotate works only with --check and defines whether to check index waiting for rotation, i.e. with .new extension. This is useful when you want to check your index before actually using it.

searchd command reference

searchd is the second of the two principle tools as part of Manticore. searchd is the part of the system which actually handles searches; it functions as a server and is responsible for receiving queries, processing them and returning a dataset back to the different APIs for client applications.

Unlike indexer, searchd is not designed to be run either from a regular script or command-line calling, but instead either as a daemon to be called from init.d (on Unix/Linux type systems) or to be called as a service (on Windows-type systems), so not all of the command line options will always apply, and so will be build-dependent.

Calling searchd is simply a case of:

$ searchd [OPTIONS]

The options available to searchd on all builds are:

  • --help (-h for short) lists all of the parameters that can be called in your particular build of searchd.

  • --config <file> (-c <file> for short) tells searchd to use the given file as its configuration, just as with indexer above.

  • --stop is used to asynchronously stop searchd, using the details of the PID file as specified in the sphinx.conf file, so you may also need to confirm to searchd which configuration file to use with the --config option. NB, calling --stop will also make sure any changes applied to the indexes with :ref:`UpdateAttributes() <update_attributes>` will be applied to the index files themselves. Example:

    $ searchd --config /home/myuser/sphinx.conf --stop
    
  • --stopwait is used to synchronously stop searchd. --stop essentially tells the running instance to exit (by sending it a SIGTERM) and then immediately returns. --stopwait will also attempt to wait until the running searchd instance actually finishes the shutdown (eg. saves all the pending attribute changes) and exits. Example:

    $ searchd --config /home/myuser/sphinx.conf --stopwait
    

    Possible exit codes are as follows:

    • 0 on success;
    • 1 if connection to running searchd daemon failed;
    • 2 if daemon reported an error during shutdown;
    • 3 if daemon crashed during shutdown.
  • --status command is used to query running searchd instance status, using the connection details from the (optionally) provided configuration file. It will try to connect to the running instance using the first configured UNIX socket or TCP port. On success, it will query for a number of status and performance counter values and print them. You can use Status() API call to access the very same counters from your application. Examples:

    $ searchd --status
    $ searchd --config /home/myuser/sphinx.conf --status
    
  • --pidfile is used to explicitly force using a PID file (where the searchd process number is stored) despite any other debugging options that say otherwise (for instance, --console). This is a debugging option.

    $ searchd --console --pidfile
    
  • --console is used to force searchd into console mode; typically it will be running as a conventional server application, and will aim to dump information into the log files (as specified in sphinx.conf). Sometimes though, when debugging issues in the configuration or the daemon itself, or trying to diagnose hard-to-track-down problems, it may be easier to force it to dump information directly to the console/command line from which it is being called. Running in console mode also means that the process will not be forked (so searches are done in sequence) and logs will not be written to. (It should be noted that console mode is not the intended method for running searchd.) You can invoke it as such:

    $ searchd --config /home/myuser/sphinx.conf --console
    
  • --logdebug, --logdebugv, and --logdebugvv options enable additional debug output in the daemon log. They differ by the logging verboseness level. These are debugging options, they pollute the log a lot, and thus they should not be normally enabled. (The normal use case for these is to enable them temporarily on request, to assist with some particularly complicated debugging session.)

  • --iostats is used in conjunction with the logging options (the query_log will need to have been activated in sphinx.conf) to provide more detailed information on a per-query basis as to the input/output operations carried out in the course of that query, with a slight performance hit and of course bigger logs. Further details are available under the query log format <README> section. You might start searchd thus:

    $ searchd --config /home/myuser/sphinx.conf --iostats
    
  • --cpustats is used to provide actual CPU time report (in addition to wall time) in both query log file (for every given query) and status report (aggregated). It depends on clock_gettime() system call and might therefore be unavailable on certain systems. You might start searchd thus:

    $ searchd --config /home/myuser/sphinx.conf --cpustats
    
  • --port portnumber (-p for short) is used to specify the port that searchd should listen on, usually for debugging purposes. This will usually default to 9312, but sometimes you need to run it on a different port. Specifying it on the command line will override anything specified in the configuration file. The valid range is 0 to 65535, but ports numbered 1024 and below usually require a privileged account in order to run. An example of usage:

    $ searchd --port 9313
    
  • --listen ( address ":" port | port | path ) [ ":" protocol ] (or -l for short) Works as --port, but allow you to specify not only the port, but full path, as IP address and port, or Unix-domain socket path, that searchd will listen on. Otherwords, you can specify either an IP address (or hostname) and port number, or just a port number, or Unix socket path. If you specify port number but not the address, searchd will listen on all network interfaces. Unix path is identified by a leading slash. As the last param you can also specify a protocol handler (listener) to be used for connections on this socket. Supported protocol values are ‘sphinx’ and ‘mysql41’ (MySQL protocol used since 4.1 upto at least 5.1).

  • --index <index> (or -i <index> for short) forces this instance of searchd only to serve the specified index. Like --port, above, this is usually for debugging purposes; more long-term changes would generally be applied to the configuration file itself. Example usage:

    $ searchd --index myindex
    
  • --strip-path strips the path names from all the file names referenced from the index (stopwords, wordforms, exceptions, etc). This is useful for picking up indexes built on another machine with possibly different path layouts.

  • --replay-flags=<OPTIONS> switch can be used to specify a list of extra binary log replay options. The supported options are:

    • accept-desc-timestamp, ignore descending transaction timestamps and replay such transactions anyway (the default behavior is to exit with an error).

    Example:

    $ searchd --replay-flags=accept-desc-timestamp
    

There are some options for searchd that are specific to Windows platforms, concerning handling as a service, are only be available on Windows binaries.

Note that on Windows searchd will default to --console mode, unless you install it as a service.

  • --install installs searchd as a service into the Microsoft Management Console (Control Panel / Administrative Tools / Services). Any other parameters specified on the command line, where --install is specified will also become part of the command line on future starts of the service. For example, as part of calling searchd, you will likely also need to specify the configuration file with --config, and you would do that as well as specifying --install. Once called, the usual start/stop facilities will become available via the management console, so any methods you could use for starting, stopping and restarting services would also apply to searchd. Example:

    C:\WINDOWS\system32> C:\Manticore\bin\searchd.exe --install
       --config C:\Manticore\sphinx.conf
    

    If you wanted to have the I/O stats every time you started searchd, you would specify its option on the same line as the --install command thus:

    C:\WINDOWS\system32> C:\Manticore\bin\searchd.exe --install
       --config C:\Manticore\sphinx.conf --iostats
    
  • --delete removes the service from the Microsoft Management Console and other places where services are registered, after previously installed with --install. Note, this does not uninstall the software or delete the indexes. It means the service will not be called from the services systems, and will not be started on the machine’s next start. If currently running as a service, the current instance will not be terminated (until the next reboot, or searchd is called with --stop). If the service was installed with a custom name (with --servicename), the same name will need to be specified with --servicename when calling to uninstall. Example:

    C:\WINDOWS\system32> C:\Manticore\bin\searchd.exe --delete
    
  • --servicename <name> applies the given name to searchd when installing or deleting the service, as would appear in the Management Console; this will default to searchd, but if being deployed on servers where multiple administrators may log into the system, or a system with multiple searchd instances, a more descriptive name may be applicable. Note that unless combined with --install or --delete, this option does not do anything. Example:

    C:\WINDOWS\system32> C:\Manticore\bin\searchd.exe --install
       --config C:\Manticore\sphinx.conf --servicename ManticoreSearch
    
  • --ntservice is the option that is passed by the Management Console to searchd to invoke it as a service on Windows platforms. It would not normally be necessary to call this directly; this would normally be called by Windows when the service would be started, although if you wanted to call this as a regular service from the command-line (as the complement to --console) you could do so in theory.

  • --safetrace forces searchd to only use system backtrace() call in crash reports. In certain (rare) scenarios, this might be a “safer” way to get that report. This is a debugging option.

  • --nodetach switch (Linux only) tells searchd not to detach into background. This will also cause log entry to be printed out to console. Query processing operates as usual. This is a debugging option.

Last but not least, as every other daemon, searchd supports a number of signals.

  • SIGTERM
  • Initiates a clean shutdown. New queries will not be handled; but queries that are already started will not be forcibly interrupted.
  • SIGHUP
  • Initiates index rotation. Depending on the value of seamless_rotate setting, new queries might be shortly stalled; clients will receive temporary errors.
  • SIGUSR1
  • Forces reopen of searchd log and query log files, letting you implement log file rotation.

spelldump command reference

spelldump is one of the helper tools within the Manticore package.

It is used to extract the contents of a dictionary file that uses ispell or MySpell format, which can help build word lists for wordforms - all of the possible forms are pre-built for you.

Its general usage is:

spelldump [options] <dictionary> <affix> [result] [locale-name]

The two main parameters are the dictionary’s main file and its affix file; usually these are named as [language-prefix].dict and [language-prefix].aff and will be available with most common Linux distributions, as well as various places online.

[result] specifies where the dictionary data should be output to, and [locale-name] additionally specifies the locale details you wish to use.

There is an additional option, -c [file], which specifies a file for case conversion details.

Examples of its usage are:

spelldump en.dict en.aff
spelldump ru.dict ru.aff ru.txt ru_RU.CP1251
spelldump ru.dict ru.aff ru.txt .1251

The results file will contain a list of all the words in the dictionary in alphabetical order, output in the format of a wordforms file, which you can use to customize for your specific circumstances. An example of the result file:

zone > zone
zoned > zoned
zoning > zoning

wordbreaker command reference

wordbreaker is one of the helper tools within the Manticore package. It is used to split compound words, as usual in URLs, into its component words. For example, this tool can split “lordoftherings” into its four component words, or “http://manofsteel.warnerbros.com” into “man of steel warner bros”. This helps searching, without requiring prefixes or infixes: searching for “sphinx” wouldn’t match “sphinxsearch” but if you break the compound word and index the separate components, you’ll get a match without the costs of prefix and infix larger index files.

Examples of its usage are:

echo manofsteel | bin/wordbreaker -dict dict.txt split
    man of steel

The input stream will be separated in words using the -dict dictionary file. In no dictionary specified, wordbreaker looks in the working folder for a wordbreaker-dict.txt file. (The dictionary should match the language of the compound word.) The split command breaks words from the standard input, and outputs the result in the standard output. There are also test and bench commands that let you test the splitting quality and benchmark the splitting functionality.

Wordbreaker Wordbreaker needs a dictionary to recognize individual substrings within a string. To differentiate between different guesses, it uses the relative frequency of each word in the dictionary: higher frequency means higher split probability. You can generate such a file using the indexer tool, as in

indexer --buildstops dict.txt 100000 --buildfreqs myindex -c /path/to/sphinx.conf

which will write the 100,000 most frequent words, along with their counts, from myindex into dict.txt. The output file is a text file, so you can edit it by hand, if need be, to add or remove words.

SphinxQL reference

SphinxQL is our SQL dialect that exposes all of the search daemon functionality using a standard SQL syntax with a few Manticore-specific extensions. Everything available via the SphinxAPI is also available via SphinxQL but not vice versa; for instance, writes into RT indexes are only available via SphinxQL. This chapter documents supported SphinxQL statements syntax.

ALTER syntax

ALTER TABLE index {ADD|DROP} COLUMN column_name [{INTEGER|INT|BIGINT|FLOAT|BOOL|MULTI|MULTI64|JSON|STRING}]

It supports adding one attribute at a time for both plain and RT indexes. The int, bigint, float, bool, multi-valued, multi-valued 64bit, json and string attribute types are supported. You can add json and string attributes, but you cannot modify their values.

Implementation details. The querying of an index is impossible (because of a write lock) while adding a column. This may change in the future. The newly created attribute values are set to 0. ALTER will not work for distributed indexes and indexes without any attributes. DROP COLUMN will fail if an index has only one attribute.

ALTER RTINDEX index RECONFIGURE

ALTER can also reconfigure an existing RT index, so that new tokenization, morphology, and other text processing settings from sphinx.conf take effect on the newly INSERT-ed rows, while retaining the existing rows as they were. Internally, it forcibly saves the current RAM chunk as a new disk chunk, and adjusts the index header, so that the new rows are tokenized using the new rules. Note that as the queries are currently parsed separately for every disk chunk, this might result in warnings regarding the keyword sets mismatch.

mysql> desc plain;
+------------+-----------+
| Field      | Type      |
+------------+-----------+
| id         | bigint    |
| text       | field     |
| group_id   | uint      |
| date_added | timestamp |
+------------+-----------+
4 rows in set (0.01 sec)

mysql> alter table plain add column test integer;
Query OK, 0 rows affected (0.04 sec)

mysql> desc plain;
+------------+-----------+
| Field      | Type      |
+------------+-----------+
| id         | bigint    |
| text       | field     |
| group_id   | uint      |
| date_added | timestamp |
| test       | uint      |
+------------+-----------+
5 rows in set (0.00 sec)

mysql> alter table plain drop column group_id;
Query OK, 0 rows affected (0.01 sec)

mysql> desc plain;
+------------+-----------+
| Field      | Type      |
+------------+-----------+
| id         | bigint    |
| text       | field     |
| date_added | timestamp |
| test       | uint      |
+------------+-----------+
4 rows in set (0.00 sec)

ATTACH INDEX syntax

ATTACH INDEX diskindex TO RTINDEX rtindex

ATTACH INDEX statement lets you move data from a regular disk index to a RT index.

After a successful ATTACH, the data originally stored in the source disk index becomes a part of the target RT index, and the source disk index becomes unavailable (until the next rebuild). ATTACH does not result in any index data changes. Basically, it just renames the files (making the source index a new disk chunk of the target RT index), and updates the metadata. So it is a generally quick operation which might (frequently) complete as fast as under a second.

Note that when an index is attached to an empty RT index, the fields, attributes, and text processing settings (tokenizer, wordforms, etc) from the source index are copied over and take effect. The respective parts of the RT index definition from the configuration file will be ignored.

ATTACH INDEX comes with a number of restrictions. Most notably, the target RT index is currently required to be empty, making ATTACH INDEX a one-time conversion operation only. Those restrictions may be lifted in future releases, as we add the needed functionality to the RT indexes. The complete list is as follows.

  • Target RT index needs to be empty. (See TRUNCATE RTINDEX syntax)
  • Source disk index needs to have index_sp=0, boundary_step=0, stopword_step=1.
  • Source disk index needs to have an empty index_zones setting.
mysql> DESC rt;
+-----------+---------+
| Field     | Type    |
+-----------+---------+
| id        | integer |
| testfield | field   |
| testattr  | uint    |
+-----------+---------+
3 rows in set (0.00 sec)

mysql> SELECT * FROM rt;
Empty set (0.00 sec)

mysql> SELECT * FROM disk WHERE MATCH('test');
+------+--------+----------+------------+
| id   | weight | group_id | date_added |
+------+--------+----------+------------+
|    1 |   1304 |        1 | 1313643256 |
|    2 |   1304 |        1 | 1313643256 |
|    3 |   1304 |        1 | 1313643256 |
|    4 |   1304 |        1 | 1313643256 |
+------+--------+----------+------------+
4 rows in set (0.00 sec)

mysql> ATTACH INDEX disk TO RTINDEX rt;
Query OK, 0 rows affected (0.00 sec)

mysql> DESC rt;
+------------+-----------+
| Field      | Type      |
+------------+-----------+
| id         | integer   |
| title      | field     |
| content    | field     |
| group_id   | uint      |
| date_added | timestamp |
+------------+-----------+
5 rows in set (0.00 sec)

mysql> SELECT * FROM rt WHERE MATCH('test');
+------+--------+----------+------------+
| id   | weight | group_id | date_added |
+------+--------+----------+------------+
|    1 |   1304 |        1 | 1313643256 |
|    2 |   1304 |        1 | 1313643256 |
|    3 |   1304 |        1 | 1313643256 |
|    4 |   1304 |        1 | 1313643256 |
+------+--------+----------+------------+
4 rows in set (0.00 sec)

mysql> SELECT * FROM disk WHERE MATCH('test');
ERROR 1064 (42000): no enabled local indexes to search

BEGIN, COMMIT, and ROLLBACK syntax

START TRANSACTION | BEGIN
COMMIT
ROLLBACK
SET AUTOCOMMIT = {0 | 1}

BEGIN statement (or its START TRANSACTION alias) forcibly commits pending transaction, if any, and begins a new one. COMMIT statement commits the current transaction, making all its changes permanent. ROLLBACK statement rolls back the current transaction, canceling all its changes. SET AUTOCOMMIT controls the autocommit mode in the active session.

AUTOCOMMIT is set to 1 by default, meaning that every statement that performs any changes on any index is implicitly wrapped in BEGIN and COMMIT.

Transactions are limited to a single RT index, and also limited in size. They are atomic, consistent, overly isolated, and durable. Overly isolated means that the changes are not only invisible to the concurrent transactions but even to the current session itself.

BEGIN syntax

START TRANSACTION | BEGIN

BEGIN syntax is discussed in detail in BEGIN, COMMIT, and ROLLBACK syntax.

CALL KEYWORDS syntax

CALL KEYWORDS(text, index [, options])

CALL KEYWORDS statement splits text into particular keywords. It returns tokenized and normalized forms of the keywords, and, optionally, keyword statistics. It also returns the position of each keyword in the query and all forms of tokenized keywords in the case that lemmatizers were used.

text is the text to break down to keywords. index is the name of the index from which to take the text processing settings. options, is an optional boolean parameter that specifies whether to return document and hit occurrence statistics. options can also accept parameters for configuring folding depending on tokenization settings:

  • stats - show statistics of keywords, default is 0
  • fold_wildcards - fold wildcards, default is 1
  • fold_lemmas - fold morphological lemmas, default is 0
  • fold_blended - fold blended words, default is 0
  • expansion_limit - override expansion_limit defined in configuration, default is 0 (use value from configuration)
call keywords(
    'que*',
    'myindex',
    1 as fold_wildcards,
    1 as fold_lemmas,
    1 as fold_blended,
    1 as expansion_limit,
    1 as stats);

Default values to match previous CALL KEYWORDS output are:

call keywords(
    'que*',
    'myindex',
    1 as fold_wildcards,
    0 as fold_lemmas,
    0 as fold_blended,
    0 as expansion_limit,
    0 as stats);

CALL PQ syntax

CALL PQ(data, index[, opt_value AS opt_name[, ...]])

CALL PQ statement performs a prospective search. It returns stored queries from a percolate``index that match documents from provided``data. For more information, see Percolate Query section.

data can be a document in plain text, a JSON object containing a document or a list of documents in one of the two formats. The JSON object can contain pairs of text field names and values as well as attribute names and values.

Example:

CALL PQ ('index_name', 'single document', 0 as docs_json);
CALL PQ ('index_name', ('first document', 'second document'), 0 as docs_json );
CALL PQ ('index_name', '{"title":"single document","content":"Add your content here","category":10,"timestamp":1513725448}');
CALL PQ ('index_name', (
                          '{"title":"first document","content":"Add your content here","category":10,"timestamp":1513725448}',
                          '{"title":"second document","content":"Add more content here","category":20,"timestamp":1513758240}'
                        )
 );

A number of options can be set:

  • docs_json - 1 ( default enabled), specify if the data provides document(s) as raw string or encapsulated as JSON object
  • docs - 0 (default disabled), provide per query documents matched at result set
  • verbose - 0 (default disabled), provide extended info in SHOW META
  • query - 0 (default disabled), if true returns all information of matched stored query, otherwise it returns just the stored query ID

Example:

MySQL [(none)]> CALL PQ('pq','catch me if you can',0 AS docs_json,1 AS query);
+------+----------+------+---------+
| UID  | Query    | Tags | Filters |
+------+----------+------+---------+
|    6 | catch me |      |         |
+------+----------+------+---------+
1 row in set (0.00 sec)

CALL PQ can be followed by a SHOW META statement which provides additional meta-information about the executed prospective search.

CALL QSUGGEST syntax

CALL QSUGGEST(word, index [,options])

CALL QSUGGEST statement enumerates for a giving word all suggestions from the dictionary. This statement works only on indexes with infixing enabled and dict=keywords. It returns the suggested keywords, Levenshtein distance between the suggested and original keyword and the docs statistic of the suggested keyword. If the first parameter is a bag of words, the function will return suggestions only for the last word, ignoring the rest. Several options are supported for customization:

  • limit - returned N top matches, default is 5
  • max_edits - keep only dictionary words which Levenshtein distance is less or equal, default is 4
  • result_stats - provide Levenshtein distance and document count of the found words, default is 1 (enabled)
  • delta_len - keep only dictionary words whose length difference is less, default is 3
  • max_matches - number of matches to keep, default is 25
  • reject - defaults to 4; rejected words are matches that are not better than those already in the match queue. They are put in a rejected queue that gets reset in case one actually can go in the match queue. This parameter defines the size of the rejected queue (as reject*max(max_matched,limit)). If the rejected queue is filled, the engine stops looking for potential matches.
  • result_line - alternate mode to display the data by returning all suggests, distances and docs each per one row, default is 0
  • non_char - do not skip dictionary words with non alphabet symbols, default is 0 (skip such words)
mysql> CALL QSUGGEST('automaticlly ','forum', 5 as limit, 4 as max_edits,1 as result_stats,3 as delta_len,0 as result_line,25 as max_matches,4 as reject );
+---------------+----------+------+
| suggest       | distance | docs |
+---------------+----------+------+
| automatically | 1        | 282  |
| automaticly   | 1        | 6    |
| automaticaly  | 1        | 3    |
| automagically | 2        | 14   |
| automtically  | 2        | 1    |
+---------------+----------+------+
5 rows in set (0.00 sec)

CALL SNIPPETS syntax

CALL SNIPPETS(data, index, query[, opt_value AS opt_name[, ...]])

CALL SNIPPETS statement builds a snippet from provided data and query, using specified index settings.

data is the source data to extract a snippet from. It could be a single string, or the list of the strings enclosed in curly brackets. index is the name of the index from which to take the text processing settings. query is the full-text query to build snippets for. Additional options are documented in BuildExcerpts. Usage example:

CALL SNIPPETS('this is my document text', 'test1', 'hello world',
    5 AS around, 200 AS limit);
CALL SNIPPETS(('this is my document text','this is my another text'), 'test1', 'hello world',
    5 AS around, 200 AS limit);
CALL SNIPPETS(('data/doc1.txt','data/doc2.txt','/home/sphinx/doc3.txt'), 'test1', 'hello world',
    5 AS around, 200 AS limit, 1 AS load_files);

CALL SUGGEST syntax

CALL SUGGEST(word, index [,options])

CALL SUGGEST statement works the same as CALL QUSUGGEST, except that if a bag of words is present, the statement will return suggestions only for the first word, ignoring the rest. If the first paramenter is a word, the functionality of CALL SUGGEST and CALL QSUGGEST is the same.

Comment syntax

SphinxQL supports C-style comment syntax. Everything from an opening /* sequence to a closing */ sequence is ignored. Comments can span multiple lines, can not nest, and should not get logged. MySQL specific /*! ... */ comments are also currently ignored. (As the comments support was rather added for better compatibility with mysqldump produced dumps, rather than improving general query interoperability between Manticore and MySQL.)

SELECT /*! SQL_CALC_FOUND_ROWS */ col1 FROM table1 WHERE ...

CREATE FUNCTION syntax

CREATE FUNCTION udf_name
    RETURNS {INT | INTEGER | BIGINT | FLOAT | STRING}
    SONAME 'udf_lib_file'

CREATE FUNCTION statement installs a user-defined function (UDF) with the given name and type from the given library file. The library file must reside in a trusted plugin_dir directory. On success, the function is available for use in all subsequent queries that the server receives. Example:

mysql> CREATE FUNCTION avgmva RETURNS INTEGER SONAME 'udfexample.dll';
Query OK, 0 rows affected (0.03 sec)

mysql> SELECT *, AVGMVA(tag) AS q from test1;
+------+--------+---------+-----------+
| id   | weight | tag     | q         |
+------+--------+---------+-----------+
|    1 |      1 | 1,3,5,7 | 4.000000  |
|    2 |      1 | 2,4,6   | 4.000000  |
|    3 |      1 | 15      | 15.000000 |
|    4 |      1 | 7,40    | 23.500000 |
+------+--------+---------+-----------+

CREATE PLUGIN syntax

CREATE PLUGIN plugin_name TYPE 'plugin_type' SONAME 'plugin_library'

Loads the given library (if it is not loaded yet) and loads the specified plugin from it. The known plugin types are:

  • ranker
  • index_token_filter
  • query_token_filter

Refer to Plugins for more information regarding writing the plugins.

mysql> CREATE PLUGIN myranker TYPE 'ranker' SONAME 'myplugins.so';
Query OK, 0 rows affected (0.00 sec)

DELETE syntax

DELETE FROM index WHERE where_condition

DELETE statement is only supported for RT indexes and for distributed which contains only RT indexes as agents It deletes existing rows (documents) from an existing index based on ID.

index is the name of RT index from which the row should be deleted.

where_condition has the same syntax as in the SELECT statement (see SELECT syntax for details).

mysql> select * from rt;
+------+------+-------------+------+
| id   | gid  | mva1        | mva2 |
+------+------+-------------+------+
|  100 | 1000 | 100,201     | 100  |
|  101 | 1001 | 101,202     | 101  |
|  102 | 1002 | 102,203     | 102  |
|  103 | 1003 | 103,204     | 103  |
|  104 | 1004 | 104,204,205 | 104  |
|  105 | 1005 | 105,206     | 105  |
|  106 | 1006 | 106,207     | 106  |
|  107 | 1007 | 107,208     | 107  |
+------+------+-------------+------+
8 rows in set (0.00 sec)

mysql> delete from rt where match ('dumy') and mva1>206;
Query OK, 2 rows affected (0.00 sec)

mysql> select * from rt;
+------+------+-------------+------+
| id   | gid  | mva1        | mva2 |
+------+------+-------------+------+
|  100 | 1000 | 100,201     | 100  |
|  101 | 1001 | 101,202     | 101  |
|  102 | 1002 | 102,203     | 102  |
|  103 | 1003 | 103,204     | 103  |
|  104 | 1004 | 104,204,205 | 104  |
|  105 | 1005 | 105,206     | 105  |
+------+------+-------------+------+
6 rows in set (0.00 sec)

mysql> delete from rt where id in (100,104,105);
Query OK, 3 rows affected (0.01 sec)

mysql> select * from rt;
+------+------+---------+------+
| id   | gid  | mva1    | mva2 |
+------+------+---------+------+
|  101 | 1001 | 101,202 | 101  |
|  102 | 1002 | 102,203 | 102  |
|  103 | 1003 | 103,204 | 103  |
+------+------+---------+------+
3 rows in set (0.00 sec)

mysql> delete from rt where mva1 in (102,204);
Query OK, 2 rows affected (0.01 sec)

mysql> select * from rt;
+------+------+---------+------+
| id   | gid  | mva1    | mva2 |
+------+------+---------+------+
|  101 | 1001 | 101,202 | 101  |
+------+------+---------+------+
1 row in set (0.00 sec)

DESCRIBE syntax

{DESC | DESCRIBE} index [ LIKE pattern ]

DESCRIBE statement lists index columns and their associated types. Columns are document ID, full-text fields, and attributes. The order matches that in which fields and attributes are expected by INSERT and REPLACE statements. Column types are field, integer, timestamp, ordinal, bool, float, bigint, string, and mva. ID column will be typed as bigint. Example:

mysql> DESC rt;
+---------+---------+
| Field   | Type    |
+---------+---------+
| id      | bigint  |
| title   | field   |
| content | field   |
| gid     | integer |
+---------+---------+
4 rows in set (0.00 sec)

An optional LIKE clause is supported. Refer to SHOW META syntax for its syntax details.

DROP FUNCTION syntax

DROP FUNCTION udf_name

DROP FUNCTION statement deinstalls a user-defined function (UDF) with the given name. On success, the function is no longer available for use in subsequent queries. Pending concurrent queries will not be affected and the library unload, if necessary, will be postponed until those queries complete. Example:

mysql> DROP FUNCTION avgmva;
Query OK, 0 rows affected (0.00 sec)

DROP PLUGIN syntax

DROP PLUGIN plugin_name TYPE 'plugin_type'

Markes the specified plugin for unloading. The unloading is not immediate, because the concurrent queries might be using it. However, after a DROP new queries will not be able to use it. Then, once all the currently executing queries using it are completed, the plugin will be unloaded. Once all the plugins from the given library are unloaded, the library is also automatically unloaded.

mysql> DROP PLUGIN myranker TYPE 'ranker';
Query OK, 0 rows affected (0.00 sec)

FLUSH ATTRIBUTES syntax

FLUSH ATTRIBUTES

Flushes all in-memory attribute updates in all the active disk indexes to disk. Returns a tag that identifies the result on-disk state (basically, a number of actual disk attribute saves performed since the daemon startup).

mysql> UPDATE testindex SET channel_id=1107025 WHERE id=1;
Query OK, 1 row affected (0.04 sec)

mysql> FLUSH ATTRIBUTES;
+------+
| tag  |
+------+
|    1 |
+------+
1 row in set (0.19 sec)

FLUSH HOSTNAMES syntax

FLUSH HOSTNAMES

Renew IPs associates to agent host names. To always query the DNS for getting the host name IP, see hostname_lookup directive.

mysql> FLUSH HOSTNAMES;
Query OK, 5 rows affected (0.01 sec)

FLUSH LOGS syntax

FLUSH LOGS

Works same as system USR1 signal. Initiate reopen of searchd log and query log files, letting you implement log file rotation. Command is non-blocking (i.e., returns immediately).

mysql> FLUSH LOGS;
Query OK, 0 rows affected (0.01 sec)

FLUSH RAMCHUNK syntax

FLUSH RAMCHUNK rtindex

FLUSH RAMCHUNK forcibly creates a new disk chunk in a RT index.

Normally, RT index would flush and convert the contents of the RAM chunk into a new disk chunk automatically, once the RAM chunk reaches the maximum allowed rt_mem_limit size. However, for debugging and testing it might be useful to forcibly create a new disk chunk, and FLUSH RAMCHUNK statement does exactly that.

Note that using FLUSH RAMCHUNK increases RT index fragmentation. Most likely, you want to use FLUSH RTINDEX instead. We suggest that you abstain from using just this statement unless you’re absolutely sure what you’re doing. As the right way is to issue FLUSH RAMCHUNK with following OPTIMIZE command. Such combo allows to keep RT index fragmentation on minimum.

mysql> FLUSH RAMCHUNK rt;
Query OK, 0 rows affected (0.05 sec)

FLUSH RTINDEX syntax

FLUSH RTINDEX rtindex

FLUSH RTINDEX forcibly flushes RT index RAM chunk contents to disk.

Backing up a RT index is as simple as copying over its data files, followed by the binary log. However, recovering from that backup means that all the transactions in the log since the last successful RAM chunk write would need to be replayed. Those writes normally happen either on a clean shutdown, or periodically with a (big enough!) interval between writes specified in rt_flush_period directive. So such a backup made at an arbitrary point in time just might end up with way too much binary log data to replay.

FLUSH RTINDEX forcibly writes the RAM chunk contents to disk, and also causes the subsequent cleanup of (now-redundant) binary log files. Thus, recovering from a backup made just after FLUSH RTINDEX should be almost instant.

mysql> FLUSH RTINDEX rt;
Query OK, 0 rows affected (0.05 sec)

INSERT and REPLACE syntax

{INSERT | REPLACE} INTO index [(column, ...)]
    VALUES (value, ...)
    [, (...)]

INSERT statement is only supported for RT indexes. It inserts new rows (documents) into an existing index, with the provided column values.

ID column must be present in all cases. Rows with duplicate IDs will not be overwritten by INSERT; use REPLACE to do that. REPLACE works exactly like INSERT, except that if an old row has the same ID as a new row, the old row is deleted before the new row is inserted.

index is the name of RT index into which the new row(s) should be inserted. The optional column names list lets you only explicitly specify values for some of the columns present in the index. All the other columns will be filled with their default values (0 for scalar types, empty string for text types).

Expressions are not currently supported in INSERT and values should be explicitly specified.

Multiple rows can be inserted using a single INSERT statement by providing several comma-separated, parentheses-enclosed lists of rows values.

List of SphinxQL reserved keywords

A complete alphabetical list of keywords that are currently reserved in SphinxQL syntax (and therefore can not be used as identifiers).

AND, AS, BY, DIV, FACET, FALSE, FROM, ID, IN, INDEXES, IS, LIMIT,
LOGS, MOD, NOT, NULL, OR, ORDER, RELOAD, SELECT, SYSFILTERS, TRUE

Multi-statement queries

SphinxQL supports multi-statement queries, or batches. Possible inter-statement optimizations described in Multi-queries do apply to SphinxQL just as well. The batched queries should be separated by a semicolon. Your MySQL client library needs to support MySQL multi-query mechanism and multiple result set. For instance, mysqli interface in PHP and DBI/DBD libraries in Perl are known to work.

Here’s a PHP sample showing how to utilize mysqli interface with Manticore.

<?php

$link = mysqli_connect ( "127.0.0.1", "root", "", "", 9306 );
if ( mysqli_connect_errno() )
    die ( "connect failed: " . mysqli_connect_error() );

$batch = "SELECT * FROM test1 ORDER BY group_id ASC;";
$batch .= "SELECT * FROM test1 ORDER BY group_id DESC";

if ( !mysqli_multi_query ( $link, $batch ) )
    die ( "query failed" );

do
{
    // fetch and print result set
    if ( $result = mysqli_store_result($link) )
    {
        while ( $row = mysqli_fetch_row($result) )
            printf ( "id=%s\n", $row[0] );
        mysqli_free_result($result);
    }

    // print divider
    if ( mysqli_more_results($link) )
        printf ( "------\n" );

} while ( mysqli_next_result($link) );

Its output with the sample test1 index included with Manticore is as follows.

$ php test_multi.php
id=1
id=2
id=3
id=4
------
id=3
id=4
id=1
id=2

The following statements can currently be used in a batch: SELECT, SHOW WARNINGS, SHOW STATUS, and SHOW META. Arbitrary sequence of these statements are allowed. The results sets returned should match those that would be returned if the batched queries were sent one by one.

OPTIMIZE INDEX syntax

OPTIMIZE INDEX index_name

OPTIMIZE statement enqueues a RT index for optimization in a background thread.

Over time, RT indexes can grow fragmented into many disk chunks and/or tainted with deleted, but unpurged data, impacting search performance. When that happens, they can be optimized. Basically, the optimization pass merges together disk chunks pairs, purging off documents suppressed by K-list as it goes.

That is a lengthy and IO intensive process, so to limit the impact, all the actual merge work is executed serially in a special background thread, and the OPTIMIZE statement simply adds a job to its queue. Currently, there is no way to check the index or queue status (that might be added in the future to the SHOW INDEX STATUS and SHOW STATUS statements respectively). The optimization thread can be IO-throttled, you can control the maximum number of IOs per second and the maximum IO size with rt_merge_iops and rt_merge_maxiosize directives respectively. The optimization jobs queue is lost on daemon crash.

The RT index being optimized stays online and available for both searching and updates at (almost) all times during the optimization. It gets locked (very) briefly every time that a pair of disk chunks is merged successfully, to rename the old and the new files, and update the index header.

At the moment, OPTIMIZE needs to be issued manually, the indexes will not be optimized automatically. That might change in the future releases.

mysql> OPTIMIZE INDEX rt;
Query OK, 0 rows affected (0.00 sec)

RELOAD INDEX syntax

RELOAD INDEX idx [ FROM '/path/to/index_files' ]

RELOAD INDEX allows you to rotate indexes using SphinxQL.

It has two modes of operation. First one (without specifying a path) makes Manticore daemon check for new index files in directory specified in path. New index files must have a idx.new.sp? names.

And if you additionally specify a path, daemon will look for index files in specified directory, move them to index path, rename from index_files.sp? to idx.new.sp? and rotate them.

mysql> RELOAD INDEX plain_index;
mysql> RELOAD INDEX plain_index FROM '/home/mighty/new_index_files';

RELOAD INDEXES syntax

RELOAD INDEXES

Works same as system HUP signal. Initiates index rotation. Depending on the value of seamless_rotate setting, new queries might be shortly stalled; clients will receive temporary errors. Command is non-blocking (i.e., returns immediately).

mysql> RELOAD INDEXES;
Query OK, 0 rows affected (0.01 sec)

RELOAD PLUGINS syntax

RELOAD PLUGINS FROM SONAME 'plugin_library'

Reloads all plugins (UDFs, rankers, etc) from a given library. Reload is, in a sense, transactional: a successful reload guarantees that a) all the plugins were successfully updated with their new versions; b) the update was atomic, all the plugins were replaced at once. Atomicity means that queries using multiple functions from a reloaded library will never mix the old and new versions. The set of plugins is guaranteed to always be consistent during the RELOAD, it will be either all old, or all new.

Reload also is seamless, meaning that some version of a reloaded plugin will be available to concurrent queries at all times, and there will be no temporary disruptions. Note how this improves on using a pair of DROP and CREATE statements for reloading: with those, there is a tiny window between the DROP and the subsequent CREATE, during which the queries technically refer to an unknown plugin and will thus fail.

In case of any failure RELOAD PLUGINS does absolutely nothing, keeps the old plugins, and reports an error.

On Windows, either overwriting or deleting a DLL library currently in use seems to be an issue. However, you can still rename it, then put a new version under the old name, and RELOAD will then work. After a succesful reload you will also be able to delete the renamed old library, too.

mysql> RELOAD PLUGINS FROM SONAME 'udfexample.dll';
Query OK, 0 rows affected (0.00 sec)

REPLACE syntax

{INSERT | REPLACE} INTO index [(column, ...)]
    VALUES (value, ...)
    [, (...)]

REPLACE syntax is identical to INSERT syntax and is described in INSERT and REPLACE syntax.

ROLLBACK syntax

ROLLBACK

ROLLBACK syntax is discussed in detail in BEGIN, COMMIT, and ROLLBACK syntax.

SELECT syntax

SELECT
    select_expr [, select_expr ...]
    FROM index [, index2 ...]
    [WHERE where_condition]
    [GROUP [N] BY {col_name | expr_alias} [, {col_name | expr_alias}]]
    [WITHIN GROUP ORDER BY {col_name | expr_alias} {ASC | DESC}]
    [HAVING having_condition]
    [ORDER BY {col_name | expr_alias} {ASC | DESC} [, ...]]
    [LIMIT [offset,] row_count]
    [OPTION opt_name = opt_value [, ...]]
    [FACET facet_options[ FACET facet_options][ ...]]

SELECT statement’s syntax is based upon regular SQL but adds several Manticore-specific extensions and has a few omissions (such as (currently) missing support for JOINs). Specifically,

Column list

Column list clause. Column names, arbitrary expressions, and star (‘*’) are all allowed (ie. SELECT id, group_id*123+456 AS expr1 FROM test1 will work). Unlike in regular SQL, all computed expressions must be aliased with a valid identifier. AS is optional.

EXIST()

EXIST ( “attr-name”, default-value ) replaces non-existent columns with default values. It returns either a value of an attribute specified by ‘attr-name’, or ‘default-value’ if that attribute does not exist. It does not support STRING or MVA attributes. This function is handy when you are searching through several indexes with different schemas.

SELECT *, EXIST('gid', 6) as cnd FROM i1, i2 WHERE cnd>5

SNIPPET()

This is a wrapper around the snippets functionality, similar to what is available via CALL SNIPPETS. The first two arguments are: the text to highlight, and a query. It’s possible to pass options to function. The intended use is as follows:

SELECT id, SNIPPET(myUdf(id), 'my.query', 'limit=100')
FROM myIndex WHERE MATCH('my.query')

where myUdf() would be a UDF that fetches a document by its ID from some external storage. This enables applications to fetch the entire result set directly from Manticore in one query, without having to separately fetch the documents in the application and then send them back to Manticore for highlighting.

SNIPPET() is a so-called “post limit” function, meaning that computing snippets is postponed not just until the entire final result set is ready, but even after the LIMIT clause is applied. For example, with a LIMIT 20,10 clause, SNIPPET() will be called at most 10 times.

Table functions is a mechanism of post-query result set processing. Table functions take an arbitrary result set as their input, and return a new, processed set as their output. The first argument should be the input result set, but a table function can optionally take and handle more arguments. Table functions can completely change the result set, including the schema. For now, only built in table functions are supported. UDFs are planned when the internal call interface is stabilized. Table functions work for both outer SELECT and nested SELECT.

REMOVE_REPEATS()

REMOVE_REPEATS ( result_set, column, offset, limit ) - removes repeated adjusted rows with the same ‘column’ value.

SELECT REMOVE_REPEATS((SELECT * FROM dist1), gid, 0, 10)

FROM

FROM clause should contain the list of indexes to search through. Unlike in regular SQL, comma means enumeration of full-text indexes as in Query() API call rather than JOIN. Index name should be according to the rules of a C identifier.

WHERE

This clause will map both to fulltext query and filters. Comparison operators (=, !=, <, >, <=, >=), IN, AND, OR, NOT, and BETWEEN are all supported and map directly to filters. MATCH(‘query’) is supported and maps to fulltext query. Query will be interpreted according to full-text query language rules. There must be at most one MATCH() in the clause. {col_name | expr_alias} [NOT] IN @uservar condition syntax is supported. (Refer to SET syntax for a description of global user variables.)

GROUP BY

Supports grouping by multiple columns or computed expressions:

SELECT *, group_id*1000+article_type AS gkey FROM example GROUP BY gkey
SELECT id FROM products GROUP BY region, price

Implicit grouping supported when using aggregate functions without specifiying a GROUP BY clause. Consider these two queries:

SELECT MAX(id), MIN(id), COUNT(*) FROM books
SELECT MAX(id), MIN(id), COUNT(*), 1 AS grp FROM books GROUP BY grp

Aggregate functions (AVG(), MIN(), MAX(), SUM()) in column list clause are supported. Arguments to aggregate functions can be either plain attributes or arbitrary expressions. COUNT(*), COUNT(DISTINCT attr) are supported. Currently there can be at most one COUNT(DISTINCT) per query and an argument needs to be an attribute. Both current restrictions on COUNT(DISTINCT) might be lifted in the future. A special GROUPBY() function is also supported. It returns the GROUP BY key. That is particularly useful when grouping by an MVA value, in order to pick the specific value that was used to create the current group.

SELECT *, AVG(price) AS avgprice, COUNT(DISTINCT storeid), GROUPBY()
FROM products
WHERE MATCH('ipod')
GROUP BY vendorid

GROUP BY on a string attribute is supported, with respect for current collation (see Collations).

You can query Manticore to return (no more than) N top matches for each group accordingly to WITHIN GROUP ORDER BY.

SELECT id FROM products GROUP 3 BY category

You can sort the result set by (an alias of) the aggregate value.

SELECT group_id, MAX(id) AS max_id
FROM my_index WHERE MATCH('the')
GROUP BY group_id ORDER BY max_id DESC

GROUP_CONCAT()

When you group by an attribute, the result set only shows attributes from a single document representing the whole group. GROUP_CONCAT() produces a comma-separated list of the attribute values of all documents in the group.

SELECT id, GROUP_CONCAT(price) as pricesList, GROUPBY() AS name FROM shops GROUP BY shopName;

ZONESPANLIST()

ZONESPANLIST() function returns pairs of matched zone spans. Each pair contains the matched zone span identifier, a colon, and the order number of the matched zone span. For example, if a document reads <emphasis role=”bold”><i>text</i> the <i>text</i></emphasis>, and you query for ‘ZONESPAN:(i,b) text’, then ZONESPANLIST() will return the string “1:1 1:2 2:1” meaning that the first zone span matched “text” in spans 1 and 2, and the second zone span in span 1 only.

WITHIN GROUP ORDER BY

This is a Manticore specific extension that lets you control how the best row within a group will to be selected. The syntax matches that of regular ORDER BY clause:

    SELECT *, INTERVAL(posted,NOW()-7*86400,NOW()-86400) AS timeseg, WEIGHT() AS w
    FROM example WHERE MATCH('my search query')
    GROUP BY siteid
    WITHIN GROUP ORDER BY w DESC
    ORDER BY timeseg DESC, w DESC

WITHIN GROUP ORDER BY on a string attribute is supported, with
respect for current collation (see :ref:`collations`).

HAVING

This is used to filter on GROUP BY values. Currently supports only one filtering condition.

SELECT id FROM plain GROUP BY title HAVING group_id=16;
SELECT id FROM plain GROUP BY attribute HAVING COUNT(*)>1;

Because of HAVING is implemented as a whole result set post-processing, result set for query with HAVING could be less than max_matches` allows.

ORDER BY

Unlike in regular SQL, only column names (not expressions) are allowed and explicit ASC and DESC are required. The columns however can be computed expressions:

SELECT *, WEIGHT()*10+docboost AS skey FROM example ORDER BY skey

You can use subqueries to speed up specific searches, which involve reranking, by postponing hard (slow) calculations as late as possible. For example, SELECT id,a_slow_expression() AS cond FROM an_index ORDER BY id ASC, cond DESC LIMIT 100; could be better written as SELECT * FROM (SELECT id,a_slow_expression() AS cond FROM an_index ORDER BY id ASC LIMIT 100) ORDER BY cond DESC; because in the first case the slow expression would be evaluated for the whole set, while in the second one it would be evaluated just for a subset of values.

ORDER BY on a string attribute is supported, with respect for current collation (see Collations).

ORDER BY RAND() syntax is supported. Note that this syntax is actually going to randomize the weight values and then order matches by those randomized weights.

LIMIT

Both LIMIT N and LIMIT M,N forms are supported. Unlike in regular SQL (but like in Manticore API), an implicit LIMIT 0,20 is present by default.

OPTION

This is a Manticore specific extension that lets you control a number of per-query options. The syntax is:

OPTION <optionname>=<value> [ , ... ]

Supported options and respectively allowed values are:

  • agent_query_timeout - integer (max time in milliseconds to wait for remote queries to complete, see agent_query_timeout under Index configuration options for details)

  • boolean_simplify - 0 or 1, enables simplifying the query to speed it up

  • comment - string, user comment that gets copied to a query log file

  • cutoff - integer (max found matches threshold)

  • field_weights - a named integer list (per-field user weights for ranking)

  • global_idf - use global statistics (frequencies) from the global_idf file for IDF computations, rather than the local index statistics.

  • idf - a quoted, comma-separated list of IDF computation flags. Known flags are:

    • normalized: BM25 variant, idf = log((N-n+1)/n), as per Robertson et al
    • plain: plain variant, idf = log(N/n), as per Sparck-Jones
    • tfidf_normalized: additionally divide IDF by query word count, so that TF*IDF fits into [0, 1] range
    • tfidf_unnormalized: do not additionally divide IDF by query word count

    where N is the collection size and n is the number of matched documents.

    The historically default IDF (Inverse Document Frequency) in Manticore is equivalent to OPTION idf=&#039;normalized,tfidf_normalized&#039;, and those normalizations may cause several undesired effects.

    First, idf=normalized causes keyword penalization. For instance, if you search for [the | something] and [the] occurs in more than 50% of the documents, then documents with both keywords [the] and [something] will get less weight than documents with just one keyword [something]. Using OPTION idf=plain avoids this. Plain IDF varies in [0, log(N)] range, and keywords are never penalized; while the normalized IDF varies in [-log(N), log(N)] range, and too frequent keywords are penalized.

    Second, idf=tfidf_normalized causes IDF drift over queries. Historically, we additionally divided IDF by query keyword count, so that the entire sum(tf*idf) over all keywords would still fit into [0,1] range. However, that means that queries [word1] and [word1 | nonmatchingword2] would assign different weights to the exactly same result set, because the IDFs for both “word1” and “nonmatchingword2” would be divided by 2. OPTION idf=tfidf_unnormalized fixes that. Note that BM25, BM25A, BM25F() ranking factors will be scale accordingly once you disable this normalization.

    IDF flags can be mixed; plain and normalized are mutually exclusive; tfidf_unnormalized and tfidf_normalized are mutually exclusive; and unspecified flags in such a mutually exclusive group take their defaults. That means that OPTION idf=plain is equivalent to a complete OPTION idf=&#039;plain,tfidf_normalized&#039; specification.

  • local_df - 0 or 1,automatically sum DFs over all the local parts of a distributed index, so that the IDF is consistent (and precise) over a locally sharded index.

  • index_weights - a named integer list (per-index user weights for ranking)

  • max_matches - integer (per-query max matches value)

    Maximum amount of matches that the daemon keeps in RAM for each index and can return to the client. Default is 1000.

    Introduced in order to control and limit RAM usage, max_matches setting defines how much matches will be kept in RAM while searching each index. Every match found will still be processed; but only best N of them will be kept in memory and return to the client in the end. Assume that the index contains 2,000,000 matches for the query. You rarely (if ever) need to retrieve all of them. Rather, you need to scan all of them, but only choose “best” at most, say, 500 by some criteria (ie. sorted by relevance, or price, or anything else), and display those 500 matches to the end user in pages of 20 to 100 matches. And tracking only the best 500 matches is much more RAM and CPU efficient than keeping all 2,000,000 matches, sorting them, and then discarding everything but the first 20 needed to display the search results page. max_matches controls N in that “best N” amount.

    This parameter noticeably affects per-query RAM and CPU usage. Values of 1,000 to 10,000 are generally fine, but higher limits must be used with care. Recklessly raising max_matches to 1,000,000 means that searchd will have to allocate and initialize 1-million-entry matches buffer for every query. That will obviously increase per-query RAM usage, and in some cases can also noticeably impact performance.

  • max_query_time - integer (max search time threshold, msec)

  • max_predicted_time - integer (max predicted search time, see predicted_time_costs)

  • ranker - any of proximity_bm25, bm25, none, wordcount, proximity, matchany, fieldmask, sph04, expr, or export (refer to Search results ranking for more details on each ranker)

  • retry_count - integer (distributed retries count)

  • retry_delay - integer (distributed retry delay, msec)

  • reverse_scan - 0 or 1, lets you control the order in which full-scan query processes the rows

  • sort_method - pq (priority queue, set by default) or kbuffer (gives faster sorting for already pre-sorted data, e.g. index data sorted by id). The result set is in both cases the same; picking one option or the other may just improve (or worsen!) performance.

  • rand_seed - lets you specify a specific integer seed value for an ORDER BY RAND() query, for example: … OPTION rand_seed=1234. By default, a new and different seed value is autogenerated for every query.

  • low_priority - runs the query with idle priority.

  • expand_keywords - 0 or 1, expand keywords with exact forms and/or stars when possible (refer to expand_keywords for more details).

Example:

SELECT * FROM test WHERE MATCH('@title hello @body world')
OPTION ranker=bm25, max_matches=3000,
    field_weights=(title=10, body=3), agent_query_timeout=10000

FACET

This Manticore specific extension enables faceted search with subtree optimization. It is capable of returning multiple result sets with a single SQL statement, without the need for complicated multi-queries. FACET clauses should be written at the very end of SELECT statements with spaces between them.

FACET {expr_list} [BY {expr_list}] [ORDER BY {expr | FACET()} {ASC | DESC}] [LIMIT [offset,] count]
SELECT * FROM test FACET brand_id FACET categories;
SELECT * FROM test FACET brand_name BY brand_id ORDER BY brand_name ASC FACET property;

Working example:

mysql> SELECT *, IN(brand_id,1,2,3,4) AS b FROM facetdemo WHERE MATCH('Product') AND b=1 LIMIT 0,10
FACET brand_name, brand_id BY brand_id ORDER BY brand_id ASC
FACET property ORDER BY COUNT(*) DESC
FACET INTERVAL(price,200,400,600,800) ORDER BY FACET() ASC
FACET categories ORDER BY FACET() ASC;
+------+-------+----------+-------------------+-------------+----------+------------+------+
| id   | price | brand_id | title             | brand_name  | property | categories | **    |
+------+-------+----------+-------------------+-------------+----------+------------+------+
|    1 |   668 |        3 | Product Four Six  | Brand Three | Three    | 11,12,13   |    1 |
|    2 |   101 |        4 | Product Two Eight | Brand Four  | One      | 12,13,14   |    1 |
|    8 |   750 |        3 | Product Ten Eight | Brand Three | Five     | 13         |    1 |
|    9 |    49 |        1 | Product Ten Two   | Brand One   | Three    | 13,14,15   |    1 |
|   13 |   613 |        1 | Product Six Two   | Brand One   | Eight    | 13         |    1 |
|   20 |   985 |        2 | Product Two Six   | Brand Two   | Nine     | 10         |    1 |
|   22 |   501 |        3 | Product Five Two  | Brand Three | Four     | 12,13,14   |    1 |
|   23 |   765 |        1 | Product Six Seven | Brand One   | Nine     | 11,12      |    1 |
|   28 |   992 |        1 | Product Six Eight | Brand One   | Two      | 12,13      |    1 |
|   29 |   259 |        1 | Product Nine Ten  | Brand One   | Five     | 12,13,14   |    1 |
+------+-------+----------+-------------------+-------------+----------+------------+------+
+-------------+----------+----------+
| brand_name  | brand_id | count(*) |
+-------------+----------+----------+
| Brand One   |        1 |     1012 |
| Brand Two   |        2 |     1025 |
| Brand Three |        3 |      994 |
| Brand Four  |        4 |      973 |
+-------------+----------+----------+
+----------+----------+
| property | count(*) |
+----------+----------+
| One      |      427 |
| Five     |      420 |
| Seven    |      420 |
| Two      |      418 |
| Three    |      407 |
| Six      |      401 |
| Nine     |      396 |
| Eight    |      387 |
| Four     |      371 |
| Ten      |      357 |
+----------+----------+
+---------------------------------+----------+
| interval(price,200,400,600,800) | count(*) |
+---------------------------------+----------+
|                               0 |      799 |
|                               1 |      795 |
|                               2 |      757 |
|                               3 |      833 |
|                               4 |      820 |
+---------------------------------+----------+
+------------+----------+
| categories | count(*) |
+------------+----------+
|         10 |      961 |
|         11 |     1653 |
|         12 |     1998 |
|         13 |     2090 |
|         14 |     1058 |
|         15 |      347 |
+------------+----------+

Subselects

In format SELECT * FROM (SELECT ORDER BY cond1 LIMIT X) ORDER BY cond2 LIMIT Y. The outer select allows only ORDER BY and LIMIT clauses. Subselects currently have 2 usage cases:

  1. We have a query with 2 ranking UDFs, one very fast and the other one slow and we perform a full-text search will a big match result set. Without subselect the query would look like

    SELECT id,slow_rank() as slow,fast_rank() as fast FROM index
            WHERE MATCH(‘some common query terms’) ORDER BY fast DESC, slow DESC LIMIT 20
            OPTION max_matches=1000;
    

    With subselects the query can be rewritten as :

    SELECT * FROM
            (SELECT id,slow_rank() as slow,fast_rank() as fast FROM index WHERE
                    MATCH(‘some common query terms’)
                    ORDER BY fast DESC LIMIT 100 OPTION max_matches=1000)
    ORDER BY slow DESC LIMIT 20;
    

    In the initial query the slow_rank() UDF is computed for the entire match result set. With subselects, only fast_rank() is computed for the entire match result set, while slow_rank() is only computed for a limited set.

  2. The second case comes handy for large result set coming from a distributed index.

    For this query:

    SELECT * FROM my_dist_index WHERE some_conditions LIMIT 50000;
    

    If we have 20 nodes, each node can send back to master a number of 50K records, resulting in 20 x 50K = 1M records, however as the master sends back only 50K (out of 1M), it might be good enough for us for the nodes to send only the top 10K records. With subselect we can rewrite the query as:

    SELECT * FROM
             (SELECT * FROM my_dist_index WHERE some_conditions LIMIT 10000)
     ORDER by some_attr LIMIT 50000;
    

    In this case, the nodes receive only the inner query and execute. This means the master will receive only 20x10K=200K records. The master will take all the records received, reorder them by the OUTER clause and return the best 50K records. The subselect help reducing the traffic between the master and the nodes and also reduce the master’s computation time (as it process only 200K instead of 1M).

SELECT @@system_variable syntax

SELECT @@system_variable [LIMIT [offset,] row_count]

This is currently a placeholder query that does nothing and reports success. That is in order to keep compatibility with frameworks and connectors that automatically execute this statement.

SET syntax

SET [GLOBAL] server_variable_name = value
SET [INDEX index_name] GLOBAL @user_variable_name = (int_val1 [, int_val2, ...])
SET NAMES value
SET @@dummy_variable = ignored_value

SET statement modifies a variable value. The variable names are case-insensitive. No variable value changes survive server restart.

SET NAMES statement and SET @@variable_name syntax, both introduced do nothing. They were implemented to maintain compatibility with 3rd party MySQL client libraries, connectors, and frameworks that may need to run this statement when connecting.

There are the following classes of the variables:

  1. per-session server variable
  2. global server variable
  3. global user variable
  4. global distributed variable

Global user variables are shared between concurrent sessions. Currently, the only supported value type is the list of BIGINTs, and these variables can only be used along with IN() for filtering purpose. The intended usage scenario is uploading huge lists of values to searchd (once) and reusing them (many times) later, saving on network overheads. Global user variables might be either transferred to all agents of distributed index or set locally in case of local index defined at distibuted index. Example:

// in session 1
mysql> SET GLOBAL @myfilter=(2,3,5,7,11,13);
Query OK, 0 rows affected (0.00 sec)

// later in session 2
mysql> SELECT * FROM test1 WHERE group_id IN @myfilter;
+------+--------+----------+------------+-----------------+------+
| id   | weight | group_id | date_added | title           | tag  |
+------+--------+----------+------------+-----------------+------+
|    3 |      1 |        2 | 1299338153 | another doc     | 15   |
|    4 |      1 |        2 | 1299338153 | doc number four | 7,40 |
+------+--------+----------+------------+-----------------+------+
2 rows in set (0.02 sec)

Per-session and global server variables affect certain server settings in the respective scope. Known per-session server variables are:

  • AUTOCOMMIT = {0 | 1}
  • Whether any data modification statement should be implicitly wrapped by BEGIN and COMMIT.
  • COLLATION_CONNECTION = collation_name
  • Selects the collation to be used for ORDER BY or GROUP BY on string values in the subsequent queries. Refer to the section called “Collations” <collations> for a list of known collation names.
  • CHARACTER_SET_RESULTS = charset_name
  • Does nothing; a placeholder to support frameworks, clients, and connectors that attempt to automatically enforce a charset when connecting to a Manticore server.
  • SQL_AUTO_IS_NULL = value
  • Does nothing; a placeholder to support frameworks, clients, and connectors that attempt to automatically enforce a charset when connecting to a Manticore server.
  • SQL_MODE = value
  • Does nothing; a placeholder to support frameworks, clients, and connectors that attempt to automatically enforce a charset when connecting to a Manticore server.
  • PROFILING = {0 | 1}
  • Enables query profiling in the current session. Defaults to 0. See also SHOW PROFILE syntax.

Known global server variables are:

  • QUERY_LOG_FORMAT = {plain | sphinxql}
  • Changes the current log format.
  • LOG_LEVEL = {info | debug | debugv | debugvv}
  • Changes the current log verboseness level.
  • QCACHE_MAX_BYTES = <value>
  • Changes the query cache RAM use limit to a given value.
  • QCACHE_THRESH_MSEC = <value>
  • Changes the query cache minimum wall time threshold to a given value.
  • QCACHE_TTL_SEC = <value>
  • Changes the query cache TTL for a cached result to a given value.
  • MAINTENANCE = {0 | 1}
  • When set to 1, puts the server in maintenance mode. Only clients with vip connections can execute queries in this mode. All new non-vip incoming connections are refused.
  • GROUPING_IN_UTC = {0 | 1}
  • When set to 1, cause timed grouping functions (day(), month(), year(), yearmonth(), yearmonthday()) to be calculated in utc. Read the doc for grouping_in_utc config params for more details.

Examples:

mysql> SET autocommit=0;
Query OK, 0 rows affected (0.00 sec)

mysql> SET GLOBAL query_log_format=sphinxql;
Query OK, 0 rows affected (0.00 sec)

SET TRANSACTION syntax

SET TRANSACTION ISOLATION LEVEL { READ UNCOMMITTED
    | READ COMMITTED
    | REPEATABLE READ
    | SERIALIZABLE }

SET TRANSACTION statement does nothing. It was implemented to maintain compatibility with 3rd party MySQL client libraries, connectors, and frameworks that may need to run this statement when connecting.

Example:

mysql> SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
Query OK, 0 rows affected (0.00 sec)

SHOW AGENT STATUS

SHOW AGENT ['agent'|'index'] STATUS [ LIKE pattern ]

Displays the statistic of remote agents or distributed index. It includes the values like the age of the last request, last answer, the number of different kind of errors and successes, etc. The statistic is shown for every agent for last 1, 5 and 15 intervals, each of them of ha_period_karma seconds. The command exists only in sphinxql.

mysql> SHOW AGENT STATUS;
+------------------------------------+----------------------------+
| Variable_name                      | Value                      |
+------------------------------------+----------------------------+
| status_period_seconds              | 60                         |
| status_stored_periods              | 15                         |
| ag_0_hostname                      | 192.168.0.202:6713         |
| ag_0_references                    | 2                          |
| ag_0_lastquery                     | 0.41                       |
| ag_0_lastanswer                    | 0.19                       |
| ag_0_lastperiodmsec                | 222                        |
| ag_0_errorsarow                    | 0                          |
| ag_0_1periods_query_timeouts       | 0                          |
| ag_0_1periods_connect_timeouts     | 0                          |
| ag_0_1periods_connect_failures     | 0                          |
| ag_0_1periods_network_errors       | 0                          |
| ag_0_1periods_wrong_replies        | 0                          |
| ag_0_1periods_unexpected_closings  | 0                          |
| ag_0_1periods_warnings             | 0                          |
| ag_0_1periods_succeeded_queries    | 27                         |
| ag_0_1periods_msecsperquery        | 232.31                     |
| ag_0_5periods_query_timeouts       | 0                          |
| ag_0_5periods_connect_timeouts     | 0                          |
| ag_0_5periods_connect_failures     | 0                          |
| ag_0_5periods_network_errors       | 0                          |
| ag_0_5periods_wrong_replies        | 0                          |
| ag_0_5periods_unexpected_closings  | 0                          |
| ag_0_5periods_warnings             | 0                          |
| ag_0_5periods_succeeded_queries    | 146                        |
| ag_0_5periods_msecsperquery        | 231.83                     |
| ag_1_hostname                      | 192.168.0.202:6714         |
| ag_1_references                    | 2                          |
| ag_1_lastquery                     | 0.41                       |
| ag_1_lastanswer                    | 0.19                       |
| ag_1_lastperiodmsec                | 220                        |
| ag_1_errorsarow                    | 0                          |
| ag_1_1periods_query_timeouts       | 0                          |
| ag_1_1periods_connect_timeouts     | 0                          |
| ag_1_1periods_connect_failures     | 0                          |
| ag_1_1periods_network_errors       | 0                          |
| ag_1_1periods_wrong_replies        | 0                          |
| ag_1_1periods_unexpected_closings  | 0                          |
| ag_1_1periods_warnings             | 0                          |
| ag_1_1periods_succeeded_queries    | 27                         |
| ag_1_1periods_msecsperquery        | 231.24                     |
| ag_1_5periods_query_timeouts       | 0                          |
| ag_1_5periods_connect_timeouts     | 0                          |
| ag_1_5periods_connect_failures     | 0                          |
| ag_1_5periods_network_errors       | 0                          |
| ag_1_5periods_wrong_replies        | 0                          |
| ag_1_5periods_unexpected_closings  | 0                          |
| ag_1_5periods_warnings             | 0                          |
| ag_1_5periods_succeeded_queries    | 146                        |
| ag_1_5periods_msecsperquery        | 230.85                     |
+------------------------------------+----------------------------+
50 rows in set (0.01 sec)

An optional LIKE clause is supported. Refer to SHOW META syntax for its syntax details.

mysql> SHOW AGENT STATUS LIKE '%5period%msec%';
+-----------------------------+--------+
| Key                         | Value  |
+-----------------------------+--------+
| ag_0_5periods_msecsperquery | 234.72 |
| ag_1_5periods_msecsperquery | 233.73 |
| ag_2_5periods_msecsperquery | 343.81 |
+-----------------------------+--------+
3 rows in set (0.00 sec)

You can specify a particular agent by its address. In this case only that agent’s data will be displayed. Also, agent_ prefix will be used instead of ag_N_:

mysql> SHOW AGENT '192.168.0.202:6714' STATUS LIKE '%15periods%';
+-------------------------------------+--------+
| Variable_name                       | Value  |
+-------------------------------------+--------+
| agent_15periods_query_timeouts      | 0      |
| agent_15periods_connect_timeouts    | 0      |
| agent_15periods_connect_failures    | 0      |
| agent_15periods_network_errors      | 0      |
| agent_15periods_wrong_replies       | 0      |
| agent_15periods_unexpected_closings | 0      |
| agent_15periods_warnings            | 0      |
| agent_15periods_succeeded_queries   | 439    |
| agent_15periods_msecsperquery       | 231.73 |
+-------------------------------------+--------+
9 rows in set (0.00 sec)

Finally, you can check the status of the agents in a specific distributed index. It can be done with a SHOW AGENT ‘index’ STATUS statement. That statement shows the index HA status (ie. whether or not it uses agent mirrors at all), and then the mirror information (specifically: address, blackhole and persistent flags, and the mirror selection probability used when one of the weighted-probability strategies is in effect).

mysql> SHOW AGENT dist_index STATUS;
+--------------------------------------+--------------------------------+
| Variable_name                        | Value                          |
+--------------------------------------+--------------------------------+
| dstindex_1_is_ha                     | 1                              |
| dstindex_1mirror1_id                 | 192.168.0.202:6713:loc         |
| dstindex_1mirror1_probability_weight | 0.372864                       |
| dstindex_1mirror1_is_blackhole       | 0                              |
| dstindex_1mirror1_is_persistent      | 0                              |
| dstindex_1mirror2_id                 | 192.168.0.202:6714:loc         |
| dstindex_1mirror2_probability_weight | 0.374635                       |
| dstindex_1mirror2_is_blackhole       | 0                              |
| dstindex_1mirror2_is_persistent      | 0                              |
| dstindex_1mirror3_id                 | dev1.sphinxsearch.com:6714:loc |
| dstindex_1mirror3_probability_weight | 0.252501                       |
| dstindex_1mirror3_is_blackhole       | 0                              |
| dstindex_1mirror3_is_persistent      | 0                              |
+--------------------------------------+--------------------------------+
13 rows in set (0.00 sec)

SHOW CHARACTER SET syntax

SHOW CHARACTER SET

This is currently a placeholder query that does nothing and reports that a UTF-8 character set is available. It was added in order to keep compatibility with frameworks and connectors that automatically execute this statement.

mysql> SHOW CHARACTER SET;
+---------+---------------+-------------------+--------+
| Charset | Description   | Default collation | Maxlen |
+---------+---------------+-------------------+--------+
| utf8    | UTF-8 Unicode | utf8_general_ci   | 3      |
+---------+---------------+-------------------+--------+
1 row in set (0.00 sec)

SHOW COLLATION syntax

SHOW COLLATION

This is currently a placeholder query that does nothing and reports success. That is in order to keep compatibility with frameworks and connectors that automatically execute this statement.

mysql> SHOW COLLATION;
Query OK, 0 rows affected (0.00 sec)

SHOW DATABASES syntax

SHOW DATABASES

This is a dummy statement to support MySQL Workbench and other clients that require it. Currently, it does absolutely nothing.

SHOW INDEX SETTINGS syntax

SHOW INDEX index_name[.N | CHUNK N] SETTINGS

Displays per-index settings in a sphinx.conf compliant file format, similar to the –dumpconfig option of the indextool. The report provides a breakdown of all the index settings, including tokenizer and dictionary options. You may also specify a particular chunk number for the RT indexes.

SHOW INDEX STATUS syntax

SHOW INDEX index_name STATUS

Displays various per-index statistics. Currently, those include:

  • indexed_documents and indexed_bytes, number of the documents indexed and their text size in bytes, respectively.
  • field_tokens_XXX, sums of per-field lengths (in tokens) over the entire index (that is used internally in BM25A and BM25F functions for ranking purposes). Only available for indexes built with index_field_lengths=1.
  • ram_bytes, total size (in bytes) of the RAM-resident index portion.
  • queries time statistics of last 1 minute, 5 minutes, 15 minutes and total since daemon start;data is encapsulated as a JSON object which includes number of queries, min,max,avg,95 and 99 percentile values.
  • queries found rows statistics of last 1 minute, 5 minutes, 15 minutes and total since daemon start;data is encapsulated as a JSON object which includes number of queries, min,max,avg,95 and 99 percentile values.
mysql> SHOW INDEX lj STATUS;
+--------------------+-------------+
| Variable_name      | Value       |
+--------------------+-------------+
| index_type         | disk        |
| indexed_documents  | 2495219     |
| indexed_bytes      | 10380483879 |
| field_tokens_title | 6999145     |
| field_tokens_body  | 1501825050  |
| total_tokens       | 1508824195  |
| ram_bytes          | 305963599   |
| disk_bytes         | 5455804365  |
| mem_limit          | 536870912   |
+--------------------+-------------+
8 rows in set (0.00 sec)

SHOW META syntax

SHOW META [ LIKE pattern ]

SHOW META shows additional meta-information about the latest query such as query time and keyword statistics. IO and CPU counters will only be available if searchd was started with –iostats and –cpustats switches respectively. Additional predicted_time, dist_predicted_time, [{local|dist}]*fetched*[{docs|hits|skips}] counters will only be available if searchd was configured with predicted time costs and query had predicted_time in OPTION clause.

mysql> SELECT * FROM test1 WHERE MATCH('test|one|two');
+------+--------+----------+------------+
| id   | weight | group_id | date_added |
+------+--------+----------+------------+
|    1 |   3563 |      456 | 1231721236 |
|    2 |   2563 |      123 | 1231721236 |
|    4 |   1480 |        2 | 1231721236 |
+------+--------+----------+------------+
3 rows in set (0.01 sec)

mysql> SHOW META;
+-----------------------+-------+
| Variable_name         | Value |
+-----------------------+-------+
| total                 | 3     |
| total_found           | 3     |
| time                  | 0.005 |
| keyword[0]            | test  |
| docs[0]               | 3     |
| hits[0]               | 5     |
| keyword[1]            | one   |
| docs[1]               | 1     |
| hits[1]               | 2     |
| keyword[2]            | two   |
| docs[2]               | 1     |
| hits[2]               | 2     |
| cpu_time              | 0.350 |
| io_read_time          | 0.004 |
| io_read_ops           | 2     |
| io_read_kbytes        | 0.4   |
| io_write_time         | 0.000 |
| io_write_ops          | 0     |
| io_write_kbytes       | 0.0   |
| agents_cpu_time       | 0.000 |
| agent_io_read_time    | 0.000 |
| agent_io_read_ops     | 0     |
| agent_io_read_kbytes  | 0.0   |
| agent_io_write_time   | 0.000 |
| agent_io_write_ops    | 0     |
| agent_io_write_kbytes | 0.0   |
+-----------------------+-------+
12 rows in set (0.00 sec)

You can also use the optional LIKE clause. It lets you pick just the variables that match a pattern. The pattern syntax is that of regular SQL wildcards, that is, ‘%’ means any number of any characters, and ‘_’ means a single character:

mysql> SHOW META LIKE 'total%';
+-----------------------+-------+
| Variable_name         | Value |
+-----------------------+-------+
| total                 | 3     |
| total_found           | 3     |
+-----------------------+-------+
2 rows in set (0.00 sec)

SHOW META can be used after executing a CALL PQ statement. In this case, it provides a different output.

SHOW PLAN syntax

SHOW PLAN

SHOW PLAN displays the execution plan of the previous SELECT statement. The plan gets generated and stored during the actual execution, so profiling must be enabled in the current session before running that statement. That can be done with a SET profiling=1 statement.

Here’s a complete instrumentation example:

mysql> SET profiling=1 \G
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT id FROM lj WHERE MATCH('the i') LIMIT 1 \G
*************************** 1\. row ***************************
id: 39815
1 row in set (1.53 sec)

mysql> SHOW PLAN \G
*************************** 1\. row ***************************
Variable: transformed_tree
   Value: AND(
  AND(KEYWORD(the, querypos=1)),
  AND(KEYWORD(i, querypos=2)))
1 row in set (0.00 sec)

And here’s a less trivial example that shows how the actually evaluated query tree can be rather different from the original one because of expansions and other transformations:

mysql> SELECT * FROM test WHERE MATCH('@title abc* @body hey') \G SHOW PLAN \G
...
*************************** 1\. row ***************************
Variable: transformed_tree
   Value: AND(
  OR(fields=(title), KEYWORD(abcx, querypos=1, expanded), KEYWORD(abcm, querypos=1, expanded)),
  AND(fields=(body), KEYWORD(hey, querypos=2)))
1 row in set (0.00 sec)

SHOW PLUGINS syntax

SHOW PLUGINS

Displays all the loaded plugins and UDFs. “Type” column should be one of the udf, ranker, index_token_filter, or query_token_filter. “Users” column is the number of thread that are currently using that plugin in a query. “Extra” column is intended for various additional plugin-type specific information; currently, it shows the return type for the UDFs and is empty for all the other plugin types.

mysql> SHOW PLUGINS;
+------+----------+----------------+-------+-------+
| Type | Name     | Library        | Users | Extra |
+------+----------+----------------+-------+-------+
| udf  | sequence | udfexample.dll | 0     | INT   |
+------+----------+----------------+-------+-------+
1 row in set (0.00 sec)

SHOW PROFILE syntax

SHOW PROFILE

SHOW PROFILE shows a detailed execution profile of the previous SQL statement executed in the current SphinxQL session. Also, profiling must be enabled in the current session before running the statement to be instrumented. That can be done with a SET profiling=1 statement. By default, profiling is disabled to avoid potential performance implications, and therefore the profile will be empty.

Here’s a complete instrumentation example:

mysql> SET profiling=1;
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT id FROM lj WHERE MATCH('the test') LIMIT 1;
+--------+
| id     |
+--------+
| 946418 |
+--------+
1 row in set (0.05 sec)

mysql> SHOW PROFILE;
+--------------+----------+----------+
| Status       | Duration | Switches |
+--------------+----------+----------+
| unknown      | 0.000610 | 6        |
| net_read     | 0.000007 | 1        |
| dist_connect | 0.000036 | 1        |
| sql_parse    | 0.000048 | 1        |
| dict_setup   | 0.000001 | 1        |
| parse        | 0.000023 | 1        |
| transforms   | 0.000002 | 1        |
| init         | 0.000401 | 3        |
| open         | 0.000104 | 1        |
| read_docs    | 0.001570 | 71       |
| read_hits    | 0.003936 | 222      |
| get_docs     | 0.029837 | 1347     |
| get_hits     | 0.000548 | 1433     |
| filter       | 0.000619 | 1274     |
| rank         | 0.009892 | 2909     |
| sort         | 0.001562 | 52       |
| finalize     | 0.000250 | 1        |
| dist_wait    | 0.000000 | 1        |
| aggregate    | 0.000145 | 1        |
| net_write    | 0.000031 | 1        |
+--------------+----------+----------+
20 rows in set (0.00 sec)

Status column briefly describes where exactly (in which state) was the time spent. Duration column shows the wall clock time, in seconds. Switches column displays the number of times query engine changed to the given state. Those are just logical engine state switches and not any OS level context switches nor function calls (even though some of the sections can actually map to function calls) and they do not have any direct effect on the performance. In a sense, number of switches is just a number of times when the respective instrumentation point was hit.

States in the profile are returned in a prerecorded order that roughly maps (but is not identical) to the actual query order.

A list of states may (and will) vary over time, as we refine the states. Here’s a brief description of the currently profiled states.

  • unknown, generic catch-all state. Accounts for both not-yet-instrumented code, or just small miscellaneous tasks that do not really belong in any other state, but are too small to deserve their own state.
  • net_read, reading the query from the network (that is, the application).
  • io, generic file IO time.
  • dist_connect, connecting to remote agents in the distributed index case.
  • sql_parse, parsing the SphinxQL syntax.
  • dict_setup, dictionary and tokenizer setup.
  • parse, parsing the full-text query syntax.
  • transforms, full-text query transformations (wildcard and other expansions, simplification, etc).
  • init, initializing the query evaluation.
  • open, opening the index files.
  • read_docs, IO time spent reading document lists.
  • read_hits, IO time spent reading keyword positions.
  • get_docs, computing the matching documents.
  • get_hits, computing the matching positions.
  • filter, filtering the full-text matches.
  • rank, computing the relevance rank.
  • sort, sorting the matches.
  • finalize, finalizing the per-index search result set (last stage expressions, etc).
  • dist_wait, waiting for the remote results from the agents in the distributed index case.
  • aggregate, aggregating multiple result sets.
  • net_write, writing the result set to the network.

SHOW STATUS syntax

SHOW STATUS [ LIKE pattern ]

SHOW STATUS displays a number of useful performance counters. IO and CPU counters will only be available if searchd was started with –iostats and –cpustats switches respectively.

mysql> SHOW STATUS;
+--------------------+-------+
| Counter            | Value |
+--------------------+-------+
| uptime             | 216   |
| connections        | 3     |
| maxed_out          | 0     |
| command_search     | 0     |
| command_excerpt    | 0     |
| command_update     | 0     |
| command_keywords   | 0     |
| command_persist    | 0     |
| command_status     | 0     |
| agent_connect      | 0     |
| agent_retry        | 0     |
| queries            | 10    |
| dist_queries       | 0     |
| query_wall         | 0.075 |
| query_cpu          | OFF   |
| dist_wall          | 0.000 |
| dist_local         | 0.000 |
| dist_wait          | 0.000 |
| query_reads        | OFF   |
| query_readkb       | OFF   |
| query_readtime     | OFF   |
| avg_query_wall     | 0.007 |
| avg_query_cpu      | OFF   |
| avg_dist_wall      | 0.000 |
| avg_dist_local     | 0.000 |
| avg_dist_wait      | 0.000 |
| avg_query_reads    | OFF   |
| avg_query_readkb   | OFF   |
| avg_query_readtime | OFF   |
+--------------------+-------+
29 rows in set (0.00 sec)

An optional LIKE clause is supported. Refer to SHOW META syntax for its syntax details.

SHOW TABLES syntax

SHOW TABLES [ LIKE pattern ]

SHOW TABLES statement enumerates all currently active indexes along with their types. Existing index types are local, distributed, rt,and template respectively. Example:

mysql> SHOW TABLES;
+-------+-------------+
| Index | Type        |
+-------+-------------+
| dist1 | distributed |
| rt    | rt          |
| test1 | local       |
| test2 | local       |
+-------+-------------+
4 rows in set (0.00 sec)

An optional LIKE clause is supported. Refer to SHOW META syntax for its syntax details.

mysql> SHOW TABLES LIKE '%4';
+-------+-------------+
| Index | Type        |
+-------+-------------+
| dist4 | distributed |
+-------+-------------+
1 row in set (0.00 sec)

SHOW THREADS syntax

SHOW THREADS [ OPTION columns=width ]

SHOW THREADS lists all currently active client threads, not counting system threads. It returns a table with columns that describe:

  • thread id
  • connection protocol, possible values are sphinxapi and sphinxql
  • thread state, possible values are handshake, net_read, net_write, query, net_idle
  • time since the current state was changed (in seconds, with microsecond precision)
  • information about queries

The ‘Info’ column will be cut at the width you’ve specified in the ‘columns=width’ option (notice the third row in the example table below). This column will contain raw SphinxQL queries and, if there are API queries, full text syntax and comments will be displayed. With an API-snippet, the data size will be displayed along with the query. This column will also contain active system thread started with SYSTEM and time since current iteration started in system endless loop.

mysql> SHOW THREADS OPTION columns=50;
+------+----------+-------+----------+----------------------------------------------------+
| Tid  | Proto    | State | Time     | Info                                               |
+------+----------+-------+----------+----------------------------------------------------+
| 5168 | sphinxql | query | 0.000002 | show threads option columns=50                     |
| 5175 | sphinxql | query | 0.000002 | select * from rt where match ( 'the box' )         |
| 1168 | sphinxql | query | 0.000002 | select * from rt where match ( 'the box and faximi |
| 9580 | -        | -     | 0.019280 | SYSTEM OPTIMIZE                                    |
+------+----------+-------+----------+----------------------------------------------------+
3 row in set (0.00 sec)

SHOW VARIABLES syntax

SHOW [{GLOBAL | SESSION}] VARIABLES [WHERE variable_name='xxx']

SHOW VARIABLES statement was added to improve compatibility with 3rd party MySQL connectors and frameworks that automatically execute this statement.

It returns the current values of a few server-wide variables. Also, support for GLOBAL and SESSION clauses was added.

mysql> SHOW GLOBAL VARIABLES;
+----------------------+----------+
| Variable_name        | Value    |
+----------------------+----------+
| autocommit           | 1        |
| collation_connection | libc_ci  |
| query_log_format     | sphinxql |
| log_level            | info     |
+----------------------+----------+
4 rows in set (0.00 sec)

Support for WHERE variable_name clause was added, to help certain connectors.

SHOW WARNINGS syntax

SHOW WARNINGS

SHOW WARNINGS statement can be used to retrieve the warning produced by the latest query. The error message will be returned along with the query itself:

mysql> SELECT * FROM test1 WHERE MATCH('@@title hello') \G
ERROR 1064 (42000): index test1: syntax error, unexpected TOK_FIELDLIMIT
near '@title hello'

mysql> SELECT * FROM test1 WHERE MATCH('@title -hello') \G
ERROR 1064 (42000): index test1: query is non-computable (single NOT operator)

mysql> SELECT * FROM test1 WHERE MATCH('"test doc"/3') \G
*************************** 1\. row ***************************
        id: 4
    weight: 2500
  group_id: 2
date_added: 1231721236
1 row in set, 1 warning (0.00 sec)

mysql> SHOW WARNINGS \G
*************************** 1\. row ***************************
  Level: warning
   Code: 1000
Message: quorum threshold too high (words=2, thresh=3); replacing quorum operator
         with AND operator
1 row in set (0.00 sec)

TRUNCATE RTINDEX syntax

TRUNCATE RTINDEX rtindex

TRUNCATE RTINDEX clears the RT index completely. It disposes the in-memory data, unlinks all the index data files, and releases the associated binary logs.

mysql> TRUNCATE RTINDEX rt;
Query OK, 0 rows affected (0.05 sec)

You may want to use this if you are using RT indices as “delta index” files; when you build the main index, you need to wipe the delta index, and thus TRUNCATE RTINDEX. You also need to use this command before attaching an index; see ATTACH INDEX syntax.

UPDATE syntax

UPDATE index SET col1 = newval1 [, ...] WHERE where_condition [OPTION opt_name = opt_value [, ...]]

Multiple attributes and values can be specified in a single statement. Both RT and disk indexes are supported.

All attributes types (int, bigint, float, MVA), except for strings and JSON attributes, can be dynamically updated.

where_condition has the same syntax as in the SELECT statement (see SELECT syntax for details).

When assigning the out-of-range values to 32-bit attributes, they will be trimmed to their lower 32 bits without a prompt. For example, if you try to update the 32-bit unsigned int with a value of 4294967297, the value of 1 will actually be stored, because the lower 32 bits of 4294967297 (0x100000001 in hex) amount to 1 (0x00000001 in hex).

MVA values sets for updating (and also for INSERT or REPLACE, refer to INSERT and REPLACE syntax) must be specified as comma-separated lists in parentheses. To erase the MVA value, just assign () to it.

UPDATE can be used to update integer and float values in JSON array. No strings, arrays and other types yet.

mysql> UPDATE myindex SET enabled=0 WHERE id=123;
Query OK, 1 rows affected (0.00 sec)

mysql> UPDATE myindex
  SET bigattr=-100000000000,
    fattr=3465.23,
    mvattr1=(3,6,4),
    mvattr2=()
  WHERE MATCH('hehe') AND enabled=1;
Query OK, 148 rows affected (0.01 sec)

OPTION clause. This is a Manticore specific extension that lets you control a number of per-update options. The syntax is:

OPTION <optionname>=<value> [ , ... ]

The list of allowed options are the same as for SELECT statement. Specifically for UPDATE statement you can use these options:

  • ‘ignore_nonexistent_columns’ - points that the update will silently ignore any warnings about trying to update a column which is not exists in current index schema.

    ‘strict’ - this option is used while updating JSON attributes. It’s possible to update just some types in JSON. And if you try to update, for example, array type you’ll get error with ‘strict’ option on and warning otherwise.

HTTP API reference

Manticore search daemon supports HTTP protocol and can be accessed with regular HTTP clients. Available only with workers = thread_pool (see workers). To enabled the HTTP protocol, a listen directive with http specified as a protocol needs to be declared:

listen = localhost:8080:http

Supported endpoints:

/search API

Allows a simple full-text search, parameters can be : * index (index or list of indexes) * match (equivalent of MATCH()) * select (as SELECT clause) * group (grouping attribute) * order (SQL-like sorting) * limit (equivalent of LIMIT 0,N)

Response is a JSON document containing an array of attrs,matches and meta similar with the SphinxAPI response.

curl -X POST 'http://manticoresearch:9308/search/'
-d 'index=forum&match=@subject php manticore&select=id,subject,author_id&limit=5'
{
   "attrs":[
          "forum_id",
          "author_id",
          "subject",
          "id"
   ],
   "matches":[

   ],
   "meta":{
          "total":0,
          "total_found":0,
          "time":0.000,
          "words":[
                 {
                        "word":"php",
                        "docs":3252,
                        "hits":11166
                 },
                 {
                        "word":"manticore",
                        "docs":0,
                        "hits":0
                 }
          ]
   }
}

/sql API

Allows running a SELECT SphinxQL, set as query parameter.

Response is a JSON document containing an array of attrs,matches and meta similar with the SphinxAPI response.

 curl -X POST 'http://manticoresearch:9308/sql/'
-d "query=select id,subject,author_id  from forum where match('@subject php manticore') group by
 author_id order by id desc limit 0,5"
{
   "attrs":[
          "forum_id",
          "author_id",
          "subject",
          "id",
          "@groupby",
          "@count"
   ],
   "matches":[

   ],
   "meta":{
          "total":123,
          "total_found":123,
          "time":0.087,
          "words":[
                 {
                        "word":"php",
                        "docs":3252,
                        "hits":11166
                 },
                 {
                        "word":"manticore",
                        "docs":1242,
                        "hits":4352
                 }
          ]
   }
}

/json API

This endpoint expects request body with queries defined as JSON document. Responds with JSON documents containing result and/or information about executed query.

Warning

Please note that this endpoint is in preview stage. Some functionalities are not yet complete and syntax may suffer changes in future. Read careful changelog of future updates to avoid possible breakages.

json/bulk

The json/bulk endpoint allows you to perform several insert, update or delete operations in a single call. This endpoint only works with data that has Content-Type set to application/x-ndjson. The data itself should be formatted as a newline-delimited json (NDJSON). Basically it means that each line should contain exactly one json statement and end with a newline \n and maybe a \r.

Example:

{ "insert" : { "index" : "test", "id" : 1, "doc": { "gid" : 10, "content" : "doc one" } } }
{ "insert" : { "index" : "test", "id" : 2, "doc": { "gid" : 20, "content" : "doc two" } } }

This inserts two documents to index test. Each statement starts with an action type (in this case, insert). Here’s a list of the supported actions:

  • insert: Inserts a document. Syntax is the same as in json/insert.
  • create: a synonym for insert
  • replace: Replaces a document. Syntax is the same as in json/replace.
  • index: a synonym for replace
  • update: Updates a document. Syntax is the same as in json/update.
  • delete: Deletes a document. Syntax is the same as in json/delete.

Updates by query and deletes by query are also supported.

Example:

{ "update" : { "index" : "test", "doc": { "tag" : 1000 }, "query": { "range": { "price": { "gte": 1000 } } } } }
{ "delete" : { "index" : "test", "query": { "range": { "price": { "lt": 1000 } } } } }

Note that the bulk operation stops at the first query that results in an error.

json/delete

This endpoint allows you to delete documents from indexes, similar to SphinxQL’s DELETE syntax.

Example:

{
  "index":"test",
  "id":1
}

The daemon will respond with a JSON object stating if the operation was successfull or not:

 {
  "_index": "test",
  "_id": 1,
  "found": true,
  "result": "deleted"
}

This deletes a document that has and id of 1 from an index named test.

As in json/update, you can do a delete by query.

{
  "index":"test",

  "query":
  {
    "match": { "*": "apple" }
  }
}

This deletes all documents that match a given query.

json/insert

Documents can be inserted into RT indexes using the /json/insert endpoint. As with SphinxQL’s INSERT and REPLACE syntax, documents with ids that already exist will not be overwritten. You can also use the /json/create endpoint, it’s a synonym for json/insert.

Here’s how you can index a simple document:

{
  "index":"test",
  "id":1
}

This creates a document with an id specified by id in an index specified by the index property. This document has empty fulltext fields and all attributes are set to their default values. However, you can use the optional doc property to set field and attribute values:

{
  "index":"test",
  "id":1,
  "doc":
  {
    "gid" : 10,
    "content" : "new document"
  }
}

The daemon will respond with a JSON object stating if the operation was successfull or not:

 {
  "_index": "test",
  "_id": 1,
  "created": true,
  "result": "created"
}

MVA attributes are inserted as arrays of numbers. JSON attributes can be inserted either as JSON objects or as strings containing escaped JSON:

{
  "index":"test",
  "id":1,
  "doc":
  {
    "mva" : [1,2,3,4,5],
    "json1":
    {
      "string": "name1",
      "int": 1,
      "array" : [100,200],
      "object": {}
    },
    "json2": "{\"string\":\"name2\",\"int\":2,\"array\":[300,400],\"object\":{}}",
    "content" : "new document"
  }
}

json/replace

json/replace works similar to SphinxQL’s INSERT and REPLACE syntax. It inserts a new document into an index and if the index already has a document with the same id, it is deleted before the new document is inserted. There’s also a synonym endpoint, json/index.

{
  "index":"test",
  "id":1,
  "doc":
  {
    "gid" : 10,
    "content" : "updated document"
  }
}

The daemon will respond with a JSON object stating if the operation was successfull or not:

 {
  "_index": "test",
  "_id": 1,
  "created": false,
  "result": "updated"
}

json/update

This endpoint allows you to update attribute values in documents, same as SphinxQL’s UPDATE syntax. Syntax is similar to json/insert, but this time the doc property is mandatory.

Example:

{
  "index":"test",
  "id":1,
  "doc":
  {
    "gid" : 100,
    "price" : 1000
  }
}

The daemon will respond with a JSON object stating if the operation was successfull or not:

 {
  "_index": "test",
  "_id": 1,
  "result": "updated"
}

The id of the document that needs to be updated can be set directly using the id property (as in the example above) or you can do an update by query and apply the update to all the documents that match the query:

{
  "index":"test",
  "doc":
  {
    "price" : 1000
  },

  "query":
  {
    "match": { "*": "apple" }
  }
}

Query syntax is the same as in the json/search endpoint. Note that you can’t specify id and query at the same time.

API reference

There is a number of native searchd client API implementations for Manticore. As of time of this writing, we officially support our own PHP, Python, and Java implementations. There also are third party free, open-source API implementations for Perl, Ruby, and C++.

The reference API implementation is in PHP, because (we believe) Manticore is most widely used with PHP than any other language. This reference documentation is in turn based on reference PHP API, and all code samples in this section will be given in PHP.

However, all other APIs provide the same methods and implement the very same network protocol. Therefore the documentation does apply to them as well. There might be minor differences as to the method naming conventions or specific data structures used. But the provided functionality must not differ across languages.

General API functions

GetLastError

Prototype: function GetLastError()

Returns last error message, as a string, in human readable format. If there were no errors during the previous API call, empty string is returned.

You should call it when any other function (such as Query()) fails (typically, the failing function returns false). The returned string will contain the error description.

The error message is not reset by this call; so you can safely call it several times if needed.

GetLastWarning

Prototype: function GetLastWarning ()

Returns last warning message, as a string, in human readable format. If there were no warnings during the previous API call, empty string is returned.

You should call it to verify whether your request (such as Query()) was completed but with warnings. For instance, search query against a distributed index might complete successfully even if several remote agents timed out. In that case, a warning message would be produced.

The warning message is not reset by this call; so you can safely call it several times if needed.

SetServer

Prototype: function SetServer ( $host, $port )

Sets searchd host name and TCP port. All subsequent requests will use the new host and port settings. Default host and port are ‘localhost’ and 9312, respectively.

SetRetries


Prototype: function SetRetries ( $count, $delay=0 )

Sets distributed retry count and delay.

On temporary failures searchd will attempt up to $count retries per agent. $delay is the delay between the retries, in milliseconds. Retries are disabled by default. Note that this call will not make the API itself retry on temporary failure; it only tells searchd to do so. Currently, the list of temporary failures includes all kinds of connect() failures and maxed out (too busy) remote agents.

SetConnectTimeout

Prototype: function SetConnectTimeout ( $timeout )

Sets the time allowed to spend connecting to the server before giving up.

Under some circumstances, the server can be delayed in responding, either due to network delays, or a query backlog. In either instance, this allows the client application programmer some degree of control over how their program interacts with searchd when not available, and can ensure that the client application does not fail due to exceeding the script execution limits (especially in PHP).

In the event of a failure to connect, an appropriate error code should be returned back to the application in order for application-level error handling to advise the user.

SetArrayResult

Prototype: function SetArrayResult ( $arrayresult )

PHP specific. Controls matches format in the search results set (whether matches should be returned as an array or a hash).

$arrayresult argument must be boolean. If $arrayresult is false (the default mode), matches will returned in PHP hash format with document IDs as keys, and other information (weight, attributes) as values. If $arrayresult is true, matches will be returned as a plain array with complete per-match information including document ID.

Introduced along with GROUP BY support on MVA attributes. Group-by-MVA result sets may contain duplicate document IDs. Thus they need to be returned as plain arrays, because hashes will only keep one entry per document ID.

IsConnectError

Prototype: function IsConnectError ()

Checks whether the last error was a network error on API side, or a remote error reported by searchd. Returns true if the last connection attempt to searchd failed on API side, false otherwise (if the error was remote, or there were no connection attempts at all).

General query settings

SetSelect

Prototype: function SetSelect ( $clause )

Sets the select clause, listing specific attributes to fetch, and Sorting modes to compute and fetch. Clause syntax mimics SQL.

SetSelect() is very similar to the part of a typical SQL query between SELECT and FROM. It lets you choose what attributes (columns) to fetch, and also what expressions over the columns to compute and fetch. A certain difference from SQL is that expressions must always be aliased to a correct identifier (consisting of letters and digits) using ‘AS’ keyword. SQL also lets you do that but does not require to. Manticore enforces aliases so that the computation results can always be returned under a “normal” name in the result set, used in other clauses, etc.

Everything else is basically identical to SQL. Star (‘*’) is supported. Functions are supported. Arbitrary amount of expressions is supported. Computed expressions can be used for sorting, filtering, and grouping, just as the regular attributes.

When using GROUP BY agregate functions (AVG(), MIN(), MAX(), SUM()) are supported.

Expression sorting (Sorting modes) and geodistance functions (SetGeoAnchor) are now internally implemented using this computed expressions mechanism, using magic names ‘@expr’ and ‘@geodist’ respectively.

Example:

$cl->SetSelect ( "*, @weight+(user_karma+ln(pageviews))*0.1 AS myweight" );
$cl->SetSelect ( "exp_years, salary_gbp*{$gbp_usd_rate} AS salary_usd,
   IF(age>40,1,0) AS over40" );
$cl->SetSelect ( "*, AVG(price) AS avgprice" );

SetLimits

Prototype: function SetLimits ( $offset, $limit, $max_matches=1000, $cutoff=0 )

Sets offset into server-side result set ($offset) and amount of matches to return to client starting from that offset ($limit). Can additionally control maximum server-side result set size for current query ($max_matches) and the threshold amount of matches to stop searching at ($cutoff). All parameters must be non-negative integers.

First two parameters to SetLimits() are identical in behavior to MySQL LIMIT clause. They instruct searchd to return at most $limit matches starting from match number $offset. The default offset and limit settings are 0 and 20, that is, to return first 20 matches.

max_matches setting controls how much matches searchd will keep in RAM while searching. All matching documents will be normally processed, ranked, filtered, and sorted even if max_matches is set to 1. But only best N documents are stored in memory at any given moment for performance and RAM usage reasons, and this setting controls that N. Note that there are two places where max_matches limit is enforced. Per-query limit is controlled by this API call, but there also is per-server limit controlled by max_matches setting in the config file. To prevent RAM usage abuse, server will not allow to set per-query limit higher than the per-server limit.

You can’t retrieve more than max_matches matches to the client application. The default limit is set to 1000. Normally, you must not have to go over this limit. One thousand records is enough to present to the end user. And if you’re thinking about pulling the results to application for further sorting or filtering, that would be much more efficient if performed on Manticore side.

$cutoff setting is intended for advanced performance control. It tells searchd to forcibly stop search query once $cutoff matches had been found and processed.

SetMaxQueryTime

Prototype: function SetMaxQueryTime ( $max_query_time )

Sets maximum search query time, in milliseconds. Parameter must be a non-negative integer. Default value is 0 which means “do not limit”.

Similar to $cutoff setting from SetLimits(), but limits elapsed query time instead of processed matches count. Local search queries will be stopped once that much time has elapsed. Note that if you’re performing a search which queries several local indexes, this limit applies to each index separately.

SetOverride

DEPRECATED

Prototype: function SetOverride ( $attrname, $attrtype, $values )

Sets temporary (per-query) per-document attribute value overrides. Only supports scalar attributes. $values must be a hash that maps document IDs to overridden attribute values.

Override feature lets you “temporary” update attribute values for some documents within a single query, leaving all other queries unaffected. This might be useful for personalized data. For example, assume you’re implementing a personalized search function that wants to boost the posts that the user’s friends recommend. Such data is not just dynamic, but also personal; so you can’t simply put it in the index because you don’t want everyone’s searches affected. Overrides, on the other hand, are local to a single query and invisible to everyone else. So you can, say, setup a “friends_weight” value for every document, defaulting to 0, then temporary override it with 1 for documents 123, 456 and 789 (recommended by exactly the friends of current user), and use that value when ranking.

Full-text search query settings

SetFieldWeights

Prototype: function SetFieldWeights ( $weights )

Binds per-field weights by name. Parameter must be a hash (associative array) mapping string field names to integer weights.

Match ranking can be affected by per-field weights. For instance, see Search results ranking for an explanation how phrase proximity ranking is affected. This call lets you specify what non-default weights to assign to different full-text fields.

The weights must be positive 32-bit integers. The final weight will be a 32-bit integer too. Default weight value is 1. Unknown field names will be silently ignored.

There is no enforced limit on the maximum weight value at the moment. However, beware that if you set it too high you can start hitting 32-bit wraparound issues. For instance, if you set a weight of 10,000,000 and search in extended mode, then maximum possible weight will be equal to 10 million (your weight) by 1 thousand (internal BM25 scaling factor, see search_results_ranking) by 1 or more (phrase proximity rank). The result is at least 10 billion that does not fit in 32 bits and will be wrapped around, producing unexpected results.

SetIndexWeights

Prototype: function SetIndexWeights ( $weights )

Sets per-index weights, and enables weighted summing of match weights across different indexes. Parameter must be a hash (associative array) mapping string index names to integer weights. Default is empty array that means to disable weighting summing.

When a match with the same document ID is found in several different local indexes, by default Manticore simply chooses the match from the index specified last in the query. This is to support searching through partially overlapping index partitions.

However in some cases the indexes are not just partitions, and you might want to sum the weights across the indexes instead of picking one. SetIndexWeights() lets you do that. With summing enabled, final match weight in result set will be computed as a sum of match weight coming from the given index multiplied by respective per-index weight specified in this call. Ie. if the document 123 is found in index A with the weight of 2, and also in index B with the weight of 3, and you called SetIndexWeights ( array ( "A"=>100, "B"=>10 ) ), the final weight return to the client will be 2100+310 = 230.

SetMatchMode

DEPRECATED

Prototype: function SetMatchMode ( $mode )

Sets full-text query matching mode, as described in Matching modes. Parameter must be a constant specifying one of the known modes.

WARNING: (PHP specific) you must not take the matching mode constant name in quotes, that syntax specifies a string and is incorrect:

$cl->SetMatchMode ( "SPH_MATCH_ANY" ); // INCORRECT! will not work as expected
$cl->SetMatchMode ( SPH_MATCH_ANY ); // correct, works OK

SetRankingMode

Prototype: function SetRankingMode ( $ranker, $rankexpr=“” )

Sets ranking mode (aka ranker). Only available in SPH_MATCH_EXTENDED matching mode. Parameter must be a constant specifying one of the known rankers.

By default, in the EXTENDED matching mode Manticore computes two factors which contribute to the final match weight. The major part is a phrase proximity value between the document text and the query. The minor part is so-called BM25 statistical function, which varies from 0 to 1 depending on the keyword frequency within document (more occurrences yield higher weight) and within the whole index (more rare keywords yield higher weight).

However, in some cases you’d want to compute weight differently - or maybe avoid computing it at all for performance reasons because you’re sorting the result set by something else anyway. This can be accomplished by setting the appropriate ranking mode. The list of the modes is available in Search results ranking.

$rankexpr argument lets you specify a ranking formula to use with the expression based ranker <expression_based_ranker_sphrank_expr>, that is, when $ranker is set to SPH_RANK_EXPR. In all other cases, $rankexpr is ignored.

SetSortMode

Prototype: function SetSortMode ( $mode, $sortby=“” )

Set matches sorting mode, as described in Sorting modes. Parameter must be a constant specifying one of the known modes.

WARNING: (PHP specific) you must not take the matching mode constant name in quotes, that syntax specifies a string and is incorrect:

$cl->SetSortMode ( "SPH_SORT_ATTR_DESC" ); // INCORRECT! will not work as expected
$cl->SetSortMode ( SPH_SORT_ATTR_ASC ); // correct, works OK

SetWeights

Prototype: function SetWeights ( $weights )

Binds per-field weights in the order of appearance in the index. DEPRECATED, use SetFieldWeights() instead.

Result set filtering settings

SetFilter

Prototype: function SetFilter ( $attribute, $values, $exclude=false )

Adds new integer values set filter.

On this call, additional new filter is added to the existing list of filters. $attribute must be a string with attribute name. $values must be a plain array containing integer values. $exclude must be a boolean value; it controls whether to accept the matching documents (default mode, when $exclude is false) or reject them.

Only those documents where $attribute column value stored in the index matches any of the values from $values array will be matched (or rejected, if $exclude is true).

SetFilterRange

Prototype: function SetFilterRange ( $attribute, $min, $max, $exclude=false )

Adds new integer range filter.

On this call, additional new filter is added to the existing list of filters. $attribute must be a string with attribute name. $min and $max must be integers that define the acceptable attribute values range (including the boundaries). $exclude must be a boolean value; it controls whether to accept the matching documents (default mode, when $exclude is false) or reject them.

Only those documents where $attribute column value stored in the index is between $min and $max (including values that are exactly equal to $min or $max) will be matched (or rejected, if $exclude is true).

SetFilterFloatRange

Prototype: function SetFilterFloatRange ( $attribute, $min, $max, $exclude=false )

Adds new float range filter.

On this call, additional new filter is added to the existing list of filters. $attribute must be a string with attribute name. $min and $max must be floats that define the acceptable attribute values range (including the boundaries). $exclude must be a boolean value; it controls whether to accept the matching documents (default mode, when $exclude is false) or reject them.

Only those documents where $attribute column value stored in the index is between $min and $max (including values that are exactly equal to $min or $max) will be matched (or rejected, if $exclude is true).

SetFilterString

Prototype: function SetFilterString ( $attribute, $value, $exclude=false )

Adds new string value filter.

On this call, additional new filter is added to the existing list of filters. $attribute must be a string with attribute name. $value must be a string. $exclude must be a boolean value; it controls whether to accept the matching documents (default mode, when $exclude is false) or reject them.

Only those documents where $attribute column value stored in the index matches string value from $value will be matched (or rejected, if $exclude is true).

SetIDRange

Prototype: function SetIDRange ( $min, $max )

Sets an accepted range of document IDs. Parameters must be integers. Defaults are 0 and 0; that combination means to not limit by range.

After this call, only those records that have document ID between $min and $max (including IDs exactly equal to $min or $max) will be matched.

SetGeoAnchor

Prototype: function SetGeoAnchor ( $attrlat, $attrlong, $lat, $long )

Sets anchor point for and geosphere distance (geodistance) calculations, and enable them.

$attrlat and $attrlong must be strings that contain the names of latitude and longitude attributes, respectively. $lat and $long are floats that specify anchor point latitude and longitude, in radians.

Once an anchor point is set, you can use magic @geodist attribute name in your filters and/or sorting expressions. Manticore will compute geosphere distance between the given anchor point and a point specified by latitude and longitude attributes from each full-text match, and attach this value to the resulting match. The latitude and longitude values both in SetGeoAnchor and the index attribute data are expected to be in radians. The result will be returned in meters, so geodistance value of 1000.0 means 1 km. 1 mile is approximately 1609.344 meters.

GROUP BY settings

SetGroupBy

Prototype: function SetGroupBy ( $attribute, $func, $groupsort=“@group desc” )

Sets grouping attribute, function, and groups sorting mode; and enables grouping (as described in Grouping (clustering) search results).

$attribute is a string that contains group-by attribute name. $func is a constant that chooses a function applied to the attribute value in order to compute group-by key. $groupsort is a clause that controls how the groups will be sorted. Its syntax is similar to that described in Sorting modes.

Grouping feature is very similar in nature to GROUP BY clause from SQL. Results produces by this function call are going to be the same as produced by the following pseudo code:

SELECT ... GROUP BY func(attribute) ORDER BY groupsort

Note that it’s $groupsort that affects the order of matches in the final result set. Sorting mode (see SetSortMode) affect the ordering of matches within group, ie. what match will be selected as the best one from the group. So you can for instance order the groups by matches count and select the most relevant match within each group at the same time.

Aggregate functions (AVG(), MIN(), MAX(), SUM()) are supported through SetSelect() API call when using GROUP BY.

Grouping on string attributes is supported, with respect to current collation.

SetGroupDistinct

Prototype: function SetGroupDistinct ( $attribute )

Sets attribute name for per-group distinct values count calculations. Only available for grouping queries.

$attribute is a string that contains the attribute name. For each group, all values of this attribute will be stored (as RAM limits permit), then the amount of distinct values will be calculated and returned to the client. This feature is similar to COUNT(DISTINCT) clause in standard SQL; so these Manticore calls:

$cl->SetGroupBy ( "category", SPH_GROUPBY_ATTR, "@count desc" );
$cl->SetGroupDistinct ( "vendor" );

can be expressed using the following SQL clauses:

SELECT id, weight, all-attributes,
    COUNT(DISTINCT vendor) AS @distinct,
    COUNT(*) AS @count
FROM products
GROUP BY category
ORDER BY @count DESC

In the sample pseudo code shown just above, SetGroupDistinct() call corresponds to COUNT(DISINCT vendor) clause only. GROUP BY, ORDER BY, and COUNT(*) clauses are all an equivalent of SetGroupBy() settings. Both queries will return one matching row for each category. In addition to indexed attributes, matches will also contain total per-category matches count, and the count of distinct vendor IDs within each category.

Querying

AddQuery

Prototype: function AddQuery ( $query, $index=“*“, $comment=”” )

Adds additional query with current settings to multi-query batch. $query is a query string. $index is an index name (or names) string. Additionally if provided, the contents of $comment are sent to the query log, marked in square brackets, just before the search terms, which can be very useful for debugging. Currently, this is limited to 128 characters. Returns index to results array returned from RunQueries.

Batch queries (or multi-queries) enable searchd to perform internal optimizations if possible. They also reduce network connection overheads and search process creation overheads in all cases. They do not result in any additional overheads compared to simple queries. Thus, if you run several different queries from your web page, you should always consider using multi-queries.

For instance, running the same full-text query but with different sorting or group-by settings will enable searchd to perform expensive full-text search and ranking operation only once, but compute multiple group-by results from its output.

This can be a big saver when you need to display not just plain search results but also some per-category counts, such as the amount of products grouped by vendor. Without multi-query, you would have to run several queries which perform essentially the same search and retrieve the same matches, but create result sets differently. With multi-query, you simply pass all these queries in a single batch and Manticore optimizes the redundant full-text search internally.

AddQuery() internally saves full current settings state along with the query, and you can safely change them afterwards for subsequent AddQuery() calls. Already added queries will not be affected; there’s actually no way to change them at all. Here’s an example:

$cl->SetSortMode ( SPH_SORT_RELEVANCE );
$cl->AddQuery ( "hello world", "documents" );

$cl->SetSortMode ( SPH_SORT_ATTR_DESC, "price" );
$cl->AddQuery ( "ipod", "products" );

$cl->AddQuery ( "harry potter", "books" );

$results = $cl->RunQueries ();

With the code above, 1st query will search for “hello world” in “documents” index and sort results by relevance, 2nd query will search for “ipod” in “products” index and sort results by price, and 3rd query will search for “harry potter” in “books” index while still sorting by price. Note that 2nd SetSortMode() call does not affect the first query (because it’s already added) but affects both other subsequent queries.

Additionally, any filters set up before an AddQuery() will fall through to subsequent queries. So, if SetFilter() is called before the first query, the same filter will be in place for the second (and subsequent) queries batched through AddQuery() unless you call ResetFilters() first. Alternatively, you can add additional filters as well.

This would also be true for grouping options and sorting options; no current sorting, filtering, and grouping settings are affected by this call; so subsequent queries will reuse current query settings.

AddQuery() returns an index into an array of results that will be returned from RunQueries() call. It is simply a sequentially increasing 0-based integer, ie. first call will return 0, second will return 1, and so on. Just a small helper so you won’t have to track the indexes manually if you need then.

Query

Prototype: function Query ( $query, $index=“*“, $comment=”” )

Connects to searchd server, runs given search query with current settings, obtains and returns the result set.

$query is a query string. $index is an index name (or names) string. Returns false and sets GetLastError() message on general error. Returns search result set on success. Additionally, the contents of $comment are sent to the query log, marked in square brackets, just before the search terms, which can be very useful for debugging. Currently, the comment is limited to 128 characters.

Default value for $index is "*" that means to query all local indexes. Characters allowed in index names include Latin letters (a-z), numbers (0-9) and underscore (_); everything else is considered a separator. Note that index name should not start with underscore character. Therefore, all of the following samples calls are valid and will search the same two indexes:

$cl->Query ( "test query", "main delta" );
$cl->Query ( "test query", "main;delta" );
$cl->Query ( "test query", "main, delta" );

Index specification order matters. If document with identical IDs are found in two or more indexes, weight and attribute values from the very last matching index will be used for sorting and returning to client (unless explicitly overridden with SetIndexWeights()). Therefore, in the example above, matches from “delta” index will always win over matches from “main”.

On success, Query() returns a result set that contains some of the found matches (as requested by SetLimits()) and additional general per-query statistics. The result set is a hash (PHP specific; other languages might utilize other structures instead of hash) with the following keys and values:

  • “matches”:
  • Hash which maps found document IDs to another small hash containing document weight and attribute values (or an array of the similar small hashes if SetArrayResult() was enabled).
  • “total”:
  • Total amount of matches retrieved on server (ie. to the server side result set) by this query. You can retrieve up to this amount of matches from server for this query text with current query settings.
  • “total_found”:
  • Total amount of matching documents in index (that were found and processed on server).
  • “words”:
  • Hash which maps query keywords (case-folded, stemmed, and otherwise processed) to a small hash with per-keyword statistics (“docs”, “hits”).
  • “error”:
  • Query error message reported by searchd (string, human readable). Empty if there were no errors.
  • “warning”:
  • Query warning message reported by searchd (string, human readable). Empty if there were no warnings.

It should be noted that Query() carries out the same actions as AddQuery() and RunQueries() without the intermediate steps; it is analogous to a single AddQuery() call, followed by a corresponding RunQueries(), then returning the first array element of matches (from the first, and only, query.)

RunQueries

Prototype: function RunQueries ()

Connect to searchd, runs a batch of all queries added using AddQuery(), obtains and returns the result sets. Returns false and sets GetLastError() message on general error (such as network I/O failure). Returns a plain array of result sets on success.

Each result set in the returned array is exactly the same as the result set returned from Query.

Note that the batch query request itself almost always succeeds - unless there’s a network error, blocking index rotation in progress, or another general failure which prevents the whole request from being processed.

However individual queries within the batch might very well fail. In this case their respective result sets will contain non-empty &quot;error&quot; message, but no matches or query statistics. In the extreme case all queries within the batch could fail. There still will be no general error reported, because API was able to successfully connect to searchd, submit the batch, and receive the results - but every result set will have a specific error message.

ResetFilters

Prototype: function ResetFilters ()

Clears all currently set filters.

This call is only normally required when using multi-queries. You might want to set different filters for different queries in the batch. To do that, you should call ResetFilters() and add new filters using the respective calls.

ResetGroupBy

Prototype: function ResetGroupBy ()

Clears all currently group-by settings, and disables group-by.

This call is only normally required when using multi-queries. You can change individual group-by settings using SetGroupBy() and SetGroupDistinct() calls, but you can not disable group-by using those calls. ResetGroupBy() fully resets previous group-by settings and disables group-by mode in the current state, so that subsequent AddQuery() calls can perform non-grouping searches.

Additional functionality

BuildExcerpts

Prototype: function BuildExcerpts ( $docs, $index, $words, $opts=array() )

Excerpts (snippets) builder function. Connects to searchd, asks it to generate excerpts (snippets) from given documents, and returns the results.

$docs is a plain array of strings that carry the documents’ contents. $index is an index name string. Different settings (such as charset, morphology, wordforms) from given index will be used. $words is a string that contains the keywords to highlight. They will be processed with respect to index settings. For instance, if English stemming is enabled in the index, shoes will be highlighted even if keyword is shoe. Keywords can contain wildcards, that work similarly to star-syntax available in queries. $opts is a hash which contains additional optional highlighting parameters:

  • before_match: A string to insert before a keyword match. A %PASSAGE_ID% macro can be used in this string. The first match of the macro is replaced with an incrementing passage number within a current snippet. Numbering starts at 1 by default but can be overridden with start_passage_id option. In a multi-document call, %PASSAGE_ID% would restart at every given document. Default is **.

  • after_match: A string to insert after a keyword match. Starting with version 1.10-beta, a %PASSAGE_ID% macro can be used in this string. Default is **.

  • chunk_separator: A string to insert between snippet chunks (passages). Default is .

  • limit: Maximum snippet size, in symbols (codepoints). Integer, default is 256.

  • around: How much words to pick around each matching keywords block. Integer, default is 5.

  • exact_phrase: Whether to highlight exact query phrase matches only instead of individual keywords. Boolean, default is false.

  • use_boundaries: Whether to additionally break passages by phrase boundary characters, as configured in index settings with phrase_boundary directive. Boolean, default is false.

  • weight_order: Whether to sort the extracted passages in order of relevance (decreasing weight), or in order of appearance in the document (increasing position). Boolean, default is false.

  • query_mode: Whether to handle $words as a query in extended syntax, or as a bag of words (default behavior). For instance, in query mode (one two | three four) will only highlight and include those occurrences one two or three four when the two words from each pair are adjacent to each other. In default mode, any single occurrence of one, two, three, or four would be highlighted. Boolean, default is false.

  • force_all_words: Ignores the snippet length limit until it includes all the keywords. Boolean, default is false.

  • limit_passages: Limits the maximum number of passages that can be included into the snippet. Integer, default is 0 (no limit).

  • limit_words: Limits the maximum number of words that can be included into the snippet. Note the limit applies to any words, and not just the matched keywords to highlight. For example, if we are highlighting Mary and a passage Mary had a little lamb is selected, then it contributes 5 words to this limit, not just 1. Integer, default is 0 (no limit).

  • start_passage_id: Specifies the starting value of %PASSAGE_ID% macro (that gets detected and expanded in before_match, after_match strings). Integer, default is 1.

  • load_files: Whether to handle $docs as data to extract snippets from (default behavior), or to treat it as file names, and load data from specified files on the server side. Up to dist_threads worker threads per request will be created to parallelize the work when this flag is enabled. Boolean, default is false. Building of the snippets could be parallelized between remote agents. Just set the ‘dist_threads’ param in the config to the value greater than 1, and then invoke the snippets generation over the distributed index, which contain only one(!) local agent and several remotes. The snippets_file_prefix option is also in the game and the final filename is calculated by concatenation of the prefix with given name. Otherwords, when snippets_file_prefix is ‘/var/data’ and filename is ‘text.txt’ the sphinx will try to generate the snippets from the file ‘/var/datatext.txt’, which is exactly ‘/var/data’ + ‘text.txt’.

  • load_files_scattered: It works only with distributed snippets generation with remote agents. The source files for snippets could be distributed among different agents, and the main daemon will merge together all non-erroneous results. So, if one agent of the distributed index has ‘file1.txt’, another has ‘file2.txt’ and you call for the snippets with both these files, the sphinx will merge results from the agents together, so you will get the snippets from both ‘file1.txt’ and ‘file2.txt’. Boolean, default is false.

    If the load_files is also set, the request will return the error in case if any of the files is not available anywhere. Otherwise (if load_files is not set) it will just return the empty strings for all absent files. The master instance reset this flag when distributes the snippets among agents. So, for agents the absence of a file is not critical error, but for the master it might be so. If you want to be sure that all snippets are actually created, set both load_files_scattered and load_files. If the absence of some snippets caused by some agents is not critical for you - set just load_files_scattered, leaving load_files not set.

  • html_strip_mode: HTML stripping mode setting. Defaults to index, which means that index settings will be used. The other values are none and strip, that forcibly skip or apply stripping irregardless of index settings; and retain, that retains HTML markup and protects it from highlighting. The retain mode can only be used when highlighting full documents and thus requires that no snippet size limits are set. String, allowed values are none, strip, index, and retain.

  • allow_empty: Allows empty string to be returned as highlighting result when a snippet could not be generated (no keywords match, or no passages fit the limit). By default, the beginning of original text would be returned instead of an empty string. Boolean, default is false.

  • passage_boundary: Ensures that passages do not cross a sentence, paragraph, or zone boundary (when used with an index that has the respective indexing settings enabled). String, allowed values are sentence, paragraph, and zone.

  • emit_zones: Emits an HTML tag with an enclosing zone name before each passage. Boolean, default is false.

Snippets extraction algorithm currently favors better passages (with closer phrase matches), and then passages with keywords not yet in snippet. Generally, it will try to highlight the best match with the query, and it will also to highlight all the query keywords, as made possible by the limits. In case the document does not match the query, beginning of the document trimmed down according to the limits will be return by default. You can also return an empty snippet instead case by setting allow_empty option to true.

Returns false on failure. Returns a plain array of strings with excerpts (snippets) on success.

BuildKeywords

Prototype: function BuildKeywords ( $query, $index, $hits )

Extracts keywords from query using tokenizer settings for given index, optionally with per-keyword occurrence statistics. Returns an array of hashes with per-keyword information.

$query is a query to extract keywords from. $index is a name of the index to get tokenizing settings and keyword occurrence statistics from. $hits is a boolean flag that indicates whether keyword occurrence statistics are required.

Usage example:

$keywords = $cl->BuildKeywords ( "this.is.my query", "test1", false );

EscapeString

Prototype: function EscapeString ( $string )

Escapes characters that are treated as special operators by the query language parser. Returns an escaped string.

$string is a string to escape.

This function might seem redundant because it’s trivial to implement in any calling application. However, as the set of special characters might change over time, it makes sense to have an API call that is guaranteed to escape all such characters at all times.

Usage example:

$escaped = $cl->EscapeString ( "escaping-sample@query/string" );

FlushAttributes

Prototype: function FlushAttributes ()

Forces searchd to flush pending attribute updates to disk, and blocks until completion. Returns a non-negative internal flush tag on success. Returns -1 and sets an error message on error.

Attribute values updated using UpdateAttributes() API call are only kept in RAM until a so-called flush (which writes the current, possibly updated attribute values back to disk). FlushAttributes() call lets you enforce a flush. The call will block until searchd finishes writing the data to disk, which might take seconds or even minutes depending on the total data size (.spa file size). All the currently updated indexes will be flushed.

Flush tag should be treated as an ever growing magic number that does not mean anything. It’s guaranteed to be non-negative. It is guaranteed to grow over time, though not necessarily in a sequential fashion; for instance, two calls that return 10 and then 1000 respectively are a valid situation. If two calls to FlushAttrs() return the same tag, it means that there were no actual attribute updates in between them, and therefore current flushed state remained the same (for all indexes).

Usage example:

$status = $cl->FlushAttributes ();
if ( $status<0 )
    print "ERROR: " . $cl->GetLastError();

Status

Prototype: function Status ()

Queries searchd status, and returns an array of status variable name and value pairs.

Usage example:

$status = $cl->Status ();
foreach ( $status as $row )
    print join ( ": ", $row ) . "\n";

UpdateAttributes

Prototype: function UpdateAttributes ( $index, $attrs, $values, $mva=false, $ignorenonexistent=false )

Instantly updates given attribute values in given documents. Returns number of actually updated documents (0 or more) on success, or -1 on failure.

$index is a name of the index (or indexes) to be updated. $attrs is a plain array with string attribute names, listing attributes that are updated. $values is a hash where key is document ID, and value is a plain array of new attribute values. Optional boolean parameter mva points that there is update of MVA attributes. In this case the values must be a dict with int key (document ID) and list of lists of int values (new MVA attribute values). Optional boolean parameter $ignorenonexistent points that the update will silently ignore any warnings about trying to update a column which is not exists in current index schema.

$index can be either a single index name or a list, like in Query(). Unlike Query(), wildcard is not allowed and all the indexes to update must be specified explicitly. The list of indexes can include distributed index names. Updates on distributed indexes will be pushed to all agents.

The updates only work with docinfo=extern storage strategy. They are very fast because they’re working fully in RAM, but they can also be made persistent: updates are saved on disk on clean searchd shutdown initiated by SIGTERM signal. With additional restrictions, updates are also possible on MVA attributes; refer to mva_updates_pool directive for details.

Usage example:

$cl->UpdateAttributes ( "test1", array("group_id"), array(1=>array(456)) );
$cl->UpdateAttributes ( "products", array ( "price", "amount_in_stock" ),
    array ( 1001=>array(123,5), 1002=>array(37,11), 1003=>(25,129) ) );

The first sample statement will update document 1 in index test1, setting group_id to 456. The second one will update documents 1001, 1002 and 1003 in index products. For document 1001, the new price will be set to 123 and the new amount in stock to 5; for document 1002, the new price will be 37 and the new amount will be 11; etc.

Persistent connections

Persistent connections allow to use single network connection to run multiple commands that would otherwise require reconnects.

Open

Prototype: function Open ()

Opens persistent connection to the server.

Close

Prototype: function Close ()

Closes previously opened persistent connection.

Configuration reference

Common section configuration options

lemmatizer_base

Lemmatizer dictionaries base path. Optional, default is /usr/local/share (as in –datadir switch to ./configure script).

Our lemmatizer implementation (see morphology for a discussion of what lemmatizers are) is dictionary driven. lemmatizer_base directive configures the base dictionary path. File names are hardcoded and specific to a given lemmatizer; the Russian lemmatizer uses ru.pak dictionary file. The dictionaries can be obtained from the Manticore website.

Example:

lemmatizer_base = /usr/local/share/sphinx/dicts/

progressive_merge

Merge Real-Time index chunks during OPTIMIZE operation from smaller to bigger. Progressive merge merger faster and reads/write less data. Enabled by default. If disabled, chunks are merged from first to last created.

json_autoconv_keynames

Whether and how to auto-convert key names within JSON attributes. Known value is ‘lowercase’. Optional, default value is unspecified (do not convert anything).

When this directive is set to ‘lowercase’, key names within JSON attributes will be automatically brought to lower case when indexing. This conversion applies to any data source, that is, JSON attributes originating from either SQL or XMLpipe2 sources will all be affected.

Example:

json_autoconv_keynames = lowercase

json_autoconv_numbers

Automatically detect and convert possible JSON strings that represent numbers, into numeric attributes. Optional, default value is 0 (do not convert strings into numbers).

When this option is 1, values such as “1234” will be indexed as numbers instead of strings; if the option is 0, such values will be indexed as strings. This conversion applies to any data source, that is, JSON attributes originating from either SQL or XMLpipe2 sources will all be affected.

Example:

json_autoconv_numbers = 1

on_json_attr_error

What to do if JSON format errors are found. Optional, default value is ignore_attr (ignore errors). Applies only to sql_attr_json attributes.

By default, JSON format errors are ignored (ignore_attr) and the indexer tool will just show a warning. Setting this option to fail_index will rather make indexing fail at the first JSON format error.

Example:

on_json_attr_error = ignore_attr

plugin_dir

Trusted location for the dynamic libraries (UDFs). Optional, default is empty (no location).

Specifies the trusted directory from which the UDF libraries can be loaded. Requires workers = thread <workers> to take effect.

Example:

plugin_dir = /usr/local/sphinx/lib

rlp_environment

RLP environment configuration file. Mandatory if RLP is used.

Example:

rlp_environment = /home/myuser/RLP/rlp-environment.xml

rlp_max_batch_docs

Maximum number of documents batched before processing them by the RLP. Optional, default is 50. This option has effect only if morphology = rlp_chinese_batched is specified.

Example:

rlp_max_batch_docs = 100

rlp_max_batch_size

Maximum total size of documents batched before processing them by the RLP. Optional, default is 51200. Do not set this value to more than 10Mb because sphinx splits large documents to 10Mb chunks before processing them by the RLP. This option has effect only if morphology = rlp_chinese_batched is specified.

Example:

rlp_max_batch_size = 100k

rlp_root

Path to the RLP root folder. Mandatory if RLP is used.

Example:

rlp_root = /home/myuser/RLP

Data source configuration options

csvpipe_delimiter

csvpipe source fields delimiter. Optional, default value is ‘,’.

Example:

csvpipe_delimiter = ;

mssql_winauth

MS SQL Windows authentication flag. Boolean, optional, default value is 0 (false). Applies to mssql source type only.

Whether to use currently logged in Windows account credentials for authentication when connecting to MS SQL Server. Note that when running searchd as a service, account user can differ from the account you used to install the service.

Example:

mssql_winauth = 1

mysql_connect_flags

MySQL client connection flags. Optional, default value is 0 (do not set any flags). Applies to mysql source type only.

This option must contain an integer value with the sum of the flags. The value will be passed to mysql_real_connect() verbatim. The flags are enumerated in mysql_com.h include file. Flags that are especially interesting in regard to indexing, with their respective values, are as follows:

  • CLIENT_COMPRESS = 32; can use compression protocol
  • CLIENT_SSL = 2048; switch to SSL after handshake
  • CLIENT_SECURE_CONNECTION = 32768; new 4.1 authentication

For instance, you can specify 2080 (2048+32) to use both compression and SSL, or 32768 to use new authentication only. Initially, this option was introduced to be able to use compression when the indexer and mysqld are on different hosts. Compression on 1 Gbps links is most likely to hurt indexing time though it reduces network traffic, both in theory and in practice. However, enabling compression on 100 Mbps links may improve indexing time significantly (upto 20-30% of the total indexing time improvement was reported). Your mileage may vary.

Example:

mysql_connect_flags = 32 # enable compression

mysql_ssl_cert, mysql_ssl_key, mysql_ssl_ca

SSL certificate settings to use for connecting to MySQL server. Optional, default values are empty strings (do not use SSL). Applies to mysql source type only.

These directives let you set up secure SSL connection between indexer and MySQL. The details on creating the certificates and setting up MySQL server can be found in MySQL documentation.

Example:

mysql_ssl_cert = /etc/ssl/client-cert.pem
mysql_ssl_key = /etc/ssl/client-key.pem
mysql_ssl_ca = /etc/ssl/cacert.pem

odbc_dsn

ODBC DSN to connect to. Mandatory, no default value. Applies to odbc source type only.

ODBC DSN (Data Source Name) specifies the credentials (host, user, password, etc) to use when connecting to ODBC data source. The format depends on specific ODBC driver used.

Example:

odbc_dsn = Driver={Oracle ODBC Driver};Dbq=myDBName;Uid=myUsername;Pwd=myPassword

sql_attr_bigint

64-bit signed integer attribute declaration. Multi-value (there might be multiple attributes declared), optional. Applies to SQL source types (mysql, pgsql, mssql) only. Note that unlike sql_attr_uint, these values are signed.

Example:

sql_attr_bigint = my_bigint_id

sql_attr_bool

Boolean attribute declaration. Multi-value (there might be multiple attributes declared), optional. Applies to SQL source types (mysql, pgsql, mssql) only. Equivalent to sql_attr_uint declaration with a bit count of 1.

Example:

sql_attr_bool = is_deleted # will be packed to 1 bit

sql_attr_float

Floating point attribute declaration. Multi-value (there might be multiple attributes declared), optional. Applies to SQL source types (mysql, pgsql, mssql) only.

The values will be stored in single precision, 32-bit IEEE 754 format. Represented range is approximately from 1e-38 to 1e+38. The amount of decimal digits that can be stored precisely is approximately 7. One important usage of the float attributes is storing latitude and longitude values (in radians), for further usage in query-time geosphere distance calculations.

Example:

sql_attr_float = lat_radians
sql_attr_float = long_radians

sql_attr_json

JSON attribute declaration. Multi-value (ie. there may be more than one such attribute declared), optional. Applies to SQL source types (mysql, pgsql, mssql) only.

When indexing JSON attributes, Manticore expects a text field with JSON formatted data. JSON attributes supports arbitrary JSON data with no limitation in nested levels or types.

{
    "id": 1,
    "gid": 2,
    "title": "some title",
    "tags": [
        "tag1",
        "tag2",
        "tag3"
        {
            "one": "two",
            "three": [4, 5]
        }
    ]
}

These attributes allow Manticore to work with documents without a fixed set of attribute columns. When you filter on a key of a JSON attribute, documents that don’t include the key will simply be ignored.

Example:

sql_attr_json = properties

sql_attr_multi

Multi-valued attribute (MVA) declaration. Multi-value (ie. there may be more than one such attribute declared), optional. Applies to SQL source types (mysql, pgsql, mssql) only.

Plain attributes only allow to attach 1 value per each document. However, there are cases (such as tags or categories) when it is desired to attach multiple values of the same attribute and be able to apply filtering or grouping to value lists.

The declaration format is as follows (backslashes are for clarity only; everything can be declared in a single line as well):

sql_attr_multi = ATTR-TYPE ATTR-NAME 'from' SOURCE-TYPE \
    [;QUERY] \
    [;RANGED-QUERY] \
    [;RANGED-MAIN-QUERY]

where

  • ATTR-TYPE is ‘uint’, ‘bigint’ or ‘timestamp’
  • SOURCE-TYPE is ‘field’, ‘query’, or ‘ranged-query’
  • QUERY is SQL query used to fetch all ( docid, attrvalue ) pairs
  • RANGED-QUERY is SQL query used to fetch min and max ID values, similar to ‘sql_query_range’
  • RANGED-MAIN-QUERY is option to use SQL query from ‘sql_query_range’

Example:

sql_attr_multi = uint tag from query; SELECT id, tag FROM tags
sql_attr_multi = bigint tag from ranged-query; \
    SELECT id, tag FROM tags WHERE id>=$start AND id<=$end; \
    SELECT MIN(id), MAX(id) FROM tags

sql_attr_string

String attribute declaration. Multi-value (ie. there may be more than one such attribute declared), optional. Applies to SQL source types (mysql, pgsql, mssql) only.

String attributes can store arbitrary strings attached to every document. There’s a fixed size limit of 4 MB per value. Also, searchd will currently cache all the values in RAM, which is an additional implicit limit.

String attributes can be used for sorting and grouping(ORDER BY, GROUP BY, WITHIN GROUP ORDER BY). Note that attributes declared using sql_attr_string will not be full-text indexed; you can use sql_field_string directive for that.

Example:

sql_attr_string = title # will be stored but will not be indexed

sql_attr_timestamp

UNIX timestamp attribute declaration. Multi-value (there might be multiple attributes declared), optional. Applies to SQL source types (mysql, pgsql, mssql) only.

Timestamps can store date and time in the range of Jan 01, 1970 to Jan 19, 2038 with a precision of one second. The expected column value should be a timestamp in UNIX format, ie. 32-bit unsigned integer number of seconds elapsed since midnight, January 01, 1970, GMT. Timestamps are internally stored and handled as integers everywhere. But in addition to working with timestamps as integers, it’s also legal to use them along with different date-based functions, such as time segments sorting mode, or day/week/month/year extraction for GROUP BY.

Note that DATE or DATETIME column types in MySQL can not be directly used as timestamp attributes in Manticore; you need to explicitly convert such columns using UNIX_TIMESTAMP function (if data is in range).

Note timestamps can not represent dates before January 01, 1970, and UNIX_TIMESTAMP() in MySQL will not return anything expected. If you only needs to work with dates, not times, consider TO_DAYS() function in MySQL instead.

Example:

# sql_query = ... UNIX_TIMESTAMP(added_datetime) AS added_ts ...
sql_attr_timestamp = added_ts

sql_attr_uint

Unsigned integer attribute declaration. Multi-value (there might be multiple attributes declared), optional. Applies to SQL source types (mysql, pgsql, mssql) only.

The column value should fit into 32-bit unsigned integer range. Values outside this range will be accepted but wrapped around. For instance, -1 will be wrapped around to 2^32-1 or 4,294,967,295.

You can specify bit count for integer attributes by appending ‘:BITCOUNT’ to attribute name (see example below). Attributes with less than default 32-bit size, or bitfields, perform slower. But they require less RAM when using extern storage: such bitfields are packed together in 32-bit chunks in .spa attribute data file. Bit size settings are ignored if using inline storage.

Example:

sql_attr_uint = group_id
sql_attr_uint = forum_id:9 # 9 bits for forum_id

sql_column_buffers

Per-column buffer sizes. Optional, default is empty (deduce the sizes automatically). Applies to odbc, mssql source types only.

ODBC and MS SQL drivers sometimes can not return the maximum actual column size to be expected. For instance, NVARCHAR(MAX) columns always report their length as 2147483647 bytes to indexer even though the actually used length is likely considerably less. However, the receiving buffers still need to be allocated upfront, and their sizes have to be determined. When the driver does not report the column length at all, Manticore allocates default 1 KB buffers for each non-char column, and 1 MB buffers for each char column. Driver-reported column length also gets clamped by an upper limit of 8 MB, so in case the driver reports (almost) a 2 GB column length, it will be clamped and a 8 MB buffer will be allocated instead for that column. These hard-coded limits can be overridden using the sql_column_buffers directive, either in order to save memory on actually shorter columns, or overcome the 8 MB limit on actually longer columns. The directive values must be a comma-separated lists of selected column names and sizes:

sql_column_buffers = <colname>=<size>[K|M] [, ...]

Example:

sql_query = SELECT id, mytitle, mycontent FROM documents
sql_column_buffers = mytitle=64K, mycontent=10M

sql_db

SQL database (in MySQL terms) to use after the connection and perform further queries within. Mandatory, no default value. Applies to SQL source types (mysql, pgsql, mssql) only.

Example:

sql_db = test

sql_field_string

Combined string attribute and full-text field declaration. Multi-value (ie. there may be more than one such attribute declared), optional. Applies to SQL source types (mysql, pgsql, mssql) only.

sql_attr_string only stores the column value but does not full-text index it. In some cases it might be desired to both full-text index the column and store it as attribute. sql_field_string lets you do exactly that. Both the field and the attribute will be named the same.

Example:

sql_field_string = title # will be both indexed and stored

sql_file_field

File based field declaration. Applies to SQL source types (mysql, pgsql, mssql) only. Introduced in version 1.10-beta.

This directive makes indexer interpret field contents as a file name, and load and index the referred file. Files larger than max_file_field_buffer in size are skipped. Any errors during the file loading (IO errors, missed limits, etc) will be reported as indexing warnings and will not early terminate the indexing. No content will be indexed for such files.

Example:

sql_file_field = my_file_path # load and index files referred to by my_file_path

sql_host

SQL server host to connect to. Mandatory, no default value. Applies to SQL source types (mysql, pgsql, mssql) only.

In the simplest case when Manticore resides on the same host with your MySQL or PostgreSQL installation, you would simply specify “localhost”. Note that MySQL client library chooses whether to connect over TCP/IP or over UNIX socket based on the host name. Specifically “localhost” will force it to use UNIX socket (this is the default and generally recommended mode) and “127.0.0.1” will force TCP/IP usage. Refer to MySQL manual for more details.

Example:

sql_host = localhost

sql_joined_field

Joined/payload field fetch query. Multi-value, optional, default is empty list of queries. Applies to SQL source types (mysql, pgsql, mssql) only.

sql_joined_field lets you use two different features: joined fields, and payloads (payload fields). It’s syntax is as follows:

sql_joined_field = FIELD-NAME 'from'  ( 'query' | 'payload-query' \
    | 'ranged-query' ); QUERY [ ; RANGE-QUERY ]

where

  • FIELD-NAME is a joined/payload field name;
  • QUERY is an SQL query that must fetch values to index.
  • RANGE-QUERY is an optional SQL query that fetches a range of values to index.

Joined fields let you avoid JOIN and/or GROUP_CONCAT statements in the main document fetch query (sql_query). This can be useful when SQL-side JOIN is slow, or needs to be offloaded on Manticore side, or simply to emulate MySQL-specific GROUP_CONCAT functionality in case your database server does not support it.

The query must return exactly 2 columns: document ID, and text to append to a joined field. Document IDs can be duplicate, but they must be in ascending order. All the text rows fetched for a given ID will be concatenated together, and the concatenation result will be indexed as the entire contents of a joined field. Rows will be concatenated in the order returned from the query, and separating whitespace will be inserted between them. For instance, if joined field query returns the following rows:

( 1, 'red' )
( 1, 'right' )
( 1, 'hand' )
( 2, 'mysql' )
( 2, 'sphinx' )

then the indexing results would be equivalent to that of adding a new text field with a value of ‘red right hand’ to document 1 and ‘mysql sphinx’ to document 2.

Joined fields are only indexed differently. There are no other differences between joined fields and regular text fields.

When a single query is not efficient enough or does not work because of the database driver limitations, ranged queries can be used. It works similar to the ranged queries in the main indexing loop, see Ranged queries. The range will be queried for and fetched upfront once, then multiple queries with different $start and $end substitutions will be run to fetch the actual data.

Payloads let you create a special field in which, instead of keyword positions, so-called user payloads are stored. Payloads are custom integer values attached to every keyword. They can then be used in search time to affect the ranking.

The payload query must return exactly 3 columns: document ID; keyword; and integer payload value. Document IDs can be duplicate, but they must be in ascending order. Payloads must be unsigned integers within 24-bit range, ie. from 0 to 16777215. For reference, payloads are currently internally stored as in-field keyword positions, but that is not guaranteed and might change in the future.

Currently, the only method to account for payloads is to use SPH_RANK_PROXIMITY_BM25 ranker. On indexes with payload fields, it will automatically switch to a variant that matches keywords in those fields, computes a sum of matched payloads multiplied by field weights, and adds that sum to the final rank.

Example:

sql_joined_field = \
    tagstext from query; \
    SELECT docid, CONCAT('tag',tagid) FROM tags ORDER BY docid ASC

sql_joined_field = bigint tag from ranged-query; \
    SELECT id, tag FROM tags WHERE id>=$start AND id<=$end ORDER BY id ASC; \
    SELECT MIN(id), MAX(id) FROM tags

sql_pass

SQL user password to use when connecting to sql_host. Mandatory, no default value. Applies to SQL source types (mysql, pgsql, mssql) only.

Example:

sql_pass = mysecretpassword

sql_port

SQL server IP port to connect to. Optional, default is 3306 for mysql source type and 5432 for pgsql type. Applies to SQL source types (mysql, pgsql, mssql) only. Note that it depends on sql_host setting whether this value will actually be used.

Example:

sql_port = 3306

sql_query_killlist

Kill-list query. Optional, default is empty (no query). Applies to SQL source types (mysql, pgsql, mssql) only.

This query is expected to return a number of 1-column rows, each containing just the document ID. The returned document IDs are stored within an index. Kill-list for a given index suppresses results from other indexes, depending on index order in the query. The intended use is to help implement deletions and updates on existing indexes without rebuilding (actually even touching them), and especially to fight phantom results problem.

Let us dissect an example. Assume we have two indexes, ‘main’ and ‘delta’. Assume that documents 2, 3, and 5 were deleted since last reindex of ‘main’, and documents 7 and 11 were updated (ie. their text contents were changed). Assume that a keyword ‘test’ occurred in all these mentioned documents when we were indexing ‘main’; still occurs in document 7 as we index ‘delta’; but does not occur in document 11 any more. We now reindex delta and then search through both these indexes in proper (least to most recent) order:

$res = $cl->Query ( "test", "main delta" );

First, we need to properly handle deletions. The result set should not contain documents 2, 3, or 5. Second, we also need to avoid phantom results. Unless we do something about it, document 11 will appear in search results! It will be found in ‘main’ (but not ‘delta’). And it will make it to the final result set unless something stops it.

Kill-list, or K-list for short, is that something. Kill-list attached to ‘delta’ will suppress the specified rows from all the preceding indexes, in this case just ‘main’. So to get the expected results, we should put all the updated and deleted document IDs into it.

Note that in the distributed index setup, K-lists are local to every node in the cluster. They are not get transmitted over the network when sending queries. (Because that might be too much of an impact when the K-list is huge.) You will need to setup a separate per-server K-lists in that case.

Example:

sql_query_killlist = \
    SELECT id FROM documents WHERE updated_ts>=@last_reindex UNION \
    SELECT id FROM documents_deleted WHERE deleted_ts>=@last_reindex

sql_query_post_index

Post-index query. Optional, default value is empty. Applies to SQL source types (mysql, pgsql, mssql) only.

This query is executed when indexing is fully and successfully completed. If this query produces errors, they are reported as warnings, but indexing is not terminated. It’s result set is ignored. $maxid macro can be used in its text; it will be expanded to maximum document ID which was actually fetched from the database during indexing. If no documents were indexed, $maxid will be expanded to 0.

Example:

sql_query_post_index = REPLACE INTO counters ( id, val ) \
    VALUES ( 'max_indexed_id', $maxid )

sql_query_post

Post-fetch query. Optional, default value is empty. Applies to SQL source types (mysql, pgsql, mssql) only.

This query is executed immediately after sql_query completes successfully. When post-fetch query produces errors, they are reported as warnings, but indexing is not terminated. It’s result set is ignored. Note that indexing is not yet completed at the point when this query gets executed, and further indexing still may fail. Therefore, any permanent updates should not be done from here. For instance, updates on helper table that permanently change the last successfully indexed ID should not be run from post-fetch query; they should be run from post-index query <sql_query_post_index> instead.

Example:

sql_query_post = DROP TABLE my_tmp_table

sql_query_pre

Pre-fetch query, or pre-query. Multi-value, optional, default is empty list of queries. Applies to SQL source types (mysql, pgsql, mssql) only.

Multi-value means that you can specify several pre-queries. They are executed before the main fetch query <sqlquery>, and they will be executed exactly in order of appearance in the configuration file. Pre-query results are ignored.

Pre-queries are useful in a lot of ways. They are used to setup encoding, mark records that are going to be indexed, update internal counters, set various per-connection SQL server options and variables, and so on.

Perhaps the most frequent pre-query usage is to specify the encoding that the server will use for the rows it returns. Note that Manticore accepts only UTF-8 texts. Two MySQL specific examples of setting the encoding are:

sql_query_pre = SET CHARACTER_SET_RESULTS=utf8
sql_query_pre = SET NAMES utf8

Also specific to MySQL sources, it is useful to disable query cache (for indexer connection only) in pre-query, because indexing queries are not going to be re-run frequently anyway, and there’s no sense in caching their results. That could be achieved with:

sql_query_pre = SET SESSION query_cache_type=OFF

Example:

sql_query_pre = SET NAMES utf8
sql_query_pre = SET SESSION query_cache_type=OFF

sql_query_range

Range query setup. Optional, default is empty. Applies to SQL source types (mysql, pgsql, mssql) only.

Setting this option enables ranged document fetch queries (see Ranged queries). Ranged queries are useful to avoid notorious MyISAM table locks when indexing lots of data. (They also help with other less notorious issues, such as reduced performance caused by big result sets, or additional resources consumed by InnoDB to serialize big read transactions.)

The query specified in this option must fetch min and max document IDs that will be used as range boundaries. It must return exactly two integer fields, min ID first and max ID second; the field names are ignored.

When ranged queries are enabled, sql_query will be required to contain $start and $end macros (because it obviously would be a mistake to index the whole table many times over). Note that the intervals specified by $start..$end will not overlap, so you should not remove document IDs that are exactly equal to $start or $end from your query. The example in Ranged queries) illustrates that; note how it uses greater-or-equal and less-or-equal comparisons.

Example:

sql_query_range = SELECT MIN(id),MAX(id) FROM documents

sql_query

Main document fetch query. Mandatory, no default value. Applies to SQL source types (mysql, pgsql, mssql) only.

There can be only one main query. This is the query which is used to retrieve documents from SQL server. You can specify up to 32 full-text fields (formally, upto SPH_MAX_FIELDS from sphinx.h), and an arbitrary amount of attributes. All of the columns that are neither document ID (the first one) nor attributes will be full-text indexed.

Document ID MUST be the very first field, and it MUST BE UNIQUE UNSIGNED POSITIVE (NON-ZERO, NON-NEGATIVE) INTEGER NUMBER.

Example:

sql_query = \
SELECT id, group_id, UNIX_TIMESTAMP(date_added) AS date_added, \
title, content \
FROM documents

sql_ranged_throttle

Ranged query throttling period, in milliseconds. Optional, default is 0 (no throttling). Applies to SQL source types (mysql, pgsql, mssql) only.

Throttling can be useful when indexer imposes too much load on the database server. It causes the indexer to sleep for given amount of milliseconds once per each ranged query step. This sleep is unconditional, and is performed before the fetch query.

Example:

sql_ranged_throttle = 1000 # sleep for 1 sec before each query step

sql_range_step

Range query step. Optional, default is 1024. Applies to SQL source types (mysql, pgsql, mssql) only.

Only used when Ranged queries are enabled. The full document IDs interval fetched by sql_query_range will be walked in this big steps. For example, if min and max IDs fetched are 12 and 3456 respectively, and the step is 1000, indexer will call sql_query several times with the following substitutions:

  • $start=12, $end=1011
  • $start=1012, $end=2011
  • $start=2012, $end=3011
  • $start=3012, $end=3456

Example:

sql_range_step = 1000

sql_sock

UNIX socket name to connect to for local SQL servers. Optional, default value is empty (use client library default settings). Applies to SQL source types (mysql, pgsql, mssql) only.

On Linux, it would typically be /var/lib/mysql/mysql.sock. On FreeBSD, it would typically be /tmp/mysql.sock. Note that it depends on sql_host setting whether this value will actually be used.

Example:

sql_sock = /tmp/mysql.sock

sql_user

SQL user to use when connecting to sql_host. Mandatory, no default value. Applies to SQL source types (mysql, pgsql, mssql) only.

Example:

sql_user = test

type

Data source type. Mandatory, no default value. Known types are mysql, pgsql, mssql, xmlpipe2, tsvpipe, csvpipe and odbc.

All other per-source options depend on source type selected by this option. Names of the options used for SQL sources (ie. MySQL, PostgreSQL, MS SQL) start with sql_; names of the ones used for xmlpipe2 or tsvpipe, csvpipe start with xmlpipe_ and tsvpipe_, csvpipe_ correspondingly. All source types are conditional; they might or might not be supported depending on your build settings, installed client libraries, etc. mssql type is currently only available on Windows. odbc type is available both on Windows natively and on Linux through UnixODBC library.

Example:

type = mysql

unpack_mysqlcompress_maxsize

Buffer size for UNCOMPRESS()ed data. Optional, default value is 16M.

When using unpack_mysqlcompress, due to implementation intricacies it is not possible to deduce the required buffer size from the compressed data. So the buffer must be preallocated in advance, and unpacked data can not go over the buffer size. This option lets you control the buffer size, both to limit indexer memory use, and to enable unpacking of really long data fields if necessary.

Example:

unpack_mysqlcompress_maxsize = 1M

unpack_mysqlcompress

Columns to unpack using MySQL UNCOMPRESS() algorithm. Multi-value, optional, default value is empty list of columns. Applies to SQL source types (mysql, pgsql, mssql) only.

Columns specified using this directive will be unpacked by indexer using modified zlib algorithm used by MySQL COMPRESS() and UNCOMPRESS() functions. When indexing on a different box than the database, this lets you offload the database, and save on network traffic. The feature is only available if zlib and zlib-devel were both available during build time.

Example:

unpack_mysqlcompress = body_compressed
unpack_mysqlcompress = description_compressed

unpack_zlib

Columns to unpack using zlib (aka deflate, aka gunzip). Multi-value, optional, default value is empty list of columns. Applies to SQL source types (mysql, pgsql, mssql) only.

Columns specified using this directive will be unpacked by indexer using standard zlib algorithm (called deflate and also implemented by gunzip). When indexing on a different box than the database, this lets you offload the database, and save on network traffic. The feature is only available if zlib and zlib-devel were both available during build time.

Example:

unpack_zlib = col1
unpack_zlib = col2

xmlpipe_attr_bigint

xmlpipe signed 64-bit integer attribute declaration. Multi-value, optional. Applies to xmlpipe2 source type only. Syntax fully matches that of sql_attr_bigint.

Example:

xmlpipe_attr_bigint = my_bigint_id

xmlpipe_attr_bool

xmlpipe boolean attribute declaration. Multi-value, optional. Applies to xmlpipe2 source type only. Syntax fully matches that of sql_attr_bool.

Example:

xmlpipe_attr_bool = is_deleted # will be packed to 1 bit

xmlpipe_attr_float

xmlpipe floating point attribute declaration. Multi-value, optional. Applies to xmlpipe2 source type only. Syntax fully matches that of sql_attr_float.

Example:

xmlpipe_attr_float = lat_radians
xmlpipe_attr_float = long_radians

xmlpipe_attr_json

JSON attribute declaration. Multi-value (ie. there may be more than one such attribute declared), optional.

This directive is used to declare that the contents of a given XML tag are to be treated as a JSON document and stored into a Manticore index for later use. Refer to sql_attr_json for more details on the JSON attributes.

Example:

xmlpipe_attr_json = properties

xmlpipe_attr_multi_64

xmlpipe MVA attribute declaration. Declares the BIGINT (signed 64-bit integer) MVA attribute. Multi-value, optional. Applies to xmlpipe2 source type only.

This setting declares an MVA attribute tag in xmlpipe2 stream. The contents of the specified tag will be parsed and a list of integers that will constitute the MVA will be extracted, similar to how sql_attr_multi parses SQL column contents when ‘field’ MVA source type is specified.

Example:

xmlpipe_attr_multi_64 = taglist

xmlpipe_attr_multi

xmlpipe MVA attribute declaration. Multi-value, optional. Applies to xmlpipe2 source type only.

This setting declares an MVA attribute tag in xmlpipe2 stream. The contents of the specified tag will be parsed and a list of integers that will constitute the MVA will be extracted, similar to how sql_attr_multi parses SQL column contents when ‘field’ MVA source type is specified.

Example:

xmlpipe_attr_multi = taglist

xmlpipe_attr_string

xmlpipe string declaration. Multi-value, optional. Applies to xmlpipe2 source type only.

This setting declares a string attribute tag in xmlpipe2 stream. The contents of the specified tag will be parsed and stored as a string value.

Example:

xmlpipe_attr_string = subject

xmlpipe_attr_timestamp

xmlpipe UNIX timestamp attribute declaration. Multi-value, optional. Applies to xmlpipe2 source type only. Syntax fully matches that of sql_attr_timestamp.

Example:

xmlpipe_attr_timestamp = published

xmlpipe_attr_uint

xmlpipe integer attribute declaration. Multi-value, optional. Applies to xmlpipe2 source type only. Syntax fully matches that of sql_attr_uint.

Example:

xmlpipe_attr_uint = author_id

xmlpipe_command

Shell command that invokes xmlpipe2 stream producer. Mandatory. Applies to xmlpipe2 source types only.

Specifies a command that will be executed and which output will be parsed for documents. Refer to xmlpipe2 data source for specific format description.

Example:

xmlpipe_command = cat /home/sphinx/test.xml

xmlpipe_field

xmlpipe field declaration. Multi-value, optional. Applies to xmlpipe2 source type only. Refer to xmlpipe2 data source.

Example:

xmlpipe_field = subject
xmlpipe_field = content

xmlpipe_field_string

xmlpipe field and string attribute declaration. Multi-value, optional. Applies to xmlpipe2 source type only. Refer to xmlpipe2 data source.

Makes the specified XML element indexed as both a full-text field and a string attribute. Equivalent to <sphinx:field name=“field” attr=“string”/> declaration within the XML file.

Example:

xmlpipe_field_string = subject

xmlpipe_fixup_utf8

Perform Manticore-side UTF-8 validation and filtering to prevent XML parser from choking on non-UTF-8 documents. Optional, default is 0. Applies to xmlpipe2 source type only.

Under certain occasions it might be hard or even impossible to guarantee that the incoming XMLpipe2 document bodies are in perfectly valid and conforming UTF-8 encoding. For instance, documents with national single-byte encodings could sneak into the stream. libexpat XML parser is fragile, meaning that it will stop processing in such cases. UTF8 fixup feature lets you avoid that. When fixup is enabled, Manticore will preprocess the incoming stream before passing it to the XML parser and replace invalid UTF-8 sequences with spaces.

Example:

xmlpipe_fixup_utf8 = 1

Index configuration options

agent_blackhole

Remote blackhole agent declaration in the distributed index <distributed_searching>. Multi-value, optional, default is empty.

agent_blackhole lets you fire-and-forget queries to remote agents. That is useful for debugging (or just testing) production clusters: you can setup a separate debugging/testing searchd instance, and forward the requests to this instance from your production master (aggregator) instance without interfering with production work. Master searchd will attempt to connect and query blackhole agent normally, but it will neither wait nor process any responses. Also, all network errors on blackhole agents will be ignored. The value format is completely identical to regular agent directive.

Example:

agent_blackhole = testbox:9312:testindex1,testindex2

agent_connect_timeout

Remote agent connection timeout, in milliseconds. Optional, default is 1000 (ie. 1 second).

When connecting to remote agents, searchd will wait at most this much time for connect() call to complete successfully. If the timeout is reached but connect() does not complete, and retries are enabled, retry will be initiated.

Example:

agent_connect_timeout = 300

agent_persistent

Persistently connected remote agent declaration. Multi-value, optional, default is empty.

agent_persistent directive syntax matches that of the agent directive. The only difference is that the master will not open a new connection to the agent for every query and then close it. Rather, it will keep a connection open and attempt to reuse for the subsequent queries. The maximal number of such persistent connections per one agent host is limited by persistent_connections_limit option of searchd section.

Note, that you have to set the last one in something greater than 0 if you want to use persistent agent connections. Otherwise - when persistent_connections_limit is not defined, it assumes the zero num of persistent connections, and ‘agent_persistent’ acts exactly as simple ‘agent’.

Persistent master-agent connections reduce TCP port pressure, and save on connection handshakes. As of time of this writing, they are supported only in workers=threads and workers=threadpool mode. In other modes, simple non-persistent connections (i.e., one connection per operation) will be used, and a warning will show up in the console.

Example:

agent_persistent = remotebox:9312:index2

agent_query_timeout

Remote agent query timeout, in milliseconds. Optional, default is 3000 (ie. 3 seconds).

After connection, searchd will wait at most this much time for remote queries to complete. This timeout is fully separate from connection timeout; so the maximum possible delay caused by a remote agent equals to the sum of agent_connection_timeout and agent_query_timeout. Queries will not be retried if this timeout is reached; a warning will be produced instead.

Example:

agent_query_timeout = 10000 # our query can be long, allow up to 10 sec

agent

Remote agent declaration in the distributed index <distributed_searching>. Multi-value, optional, default is empty.

agent directive declares remote agents that are searched every time when the enclosing distributed index is searched. The agents are, essentially, pointers to networked indexes. The value specifies address, and also can additionally specify multiple alternatives (agent mirrors) for either the address only, or the address and index list:

agent = address1 [ | address2 [...] ][:index-list]
agent = address1[:index-list [ | address2[:index-list [...] ] ] ]

In both cases the address specification must be one of the following:

address = hostname[:port] # eg. server2:9312
address = /absolute/unix/socket/path # eg. /var/run/sphinx2.sock

Where hostname is the remote host name, port is the remote TCP port number, index-list is a comma-separated list of index names, and square braces [] designate an optional clause.

When index name is omited, it is assumed the same index as the one where this line is defined. I.e. when defining agents for distributed index ‘mycoolindex’ you can just point the address, and it is assumed to calll ‘mycoolindex’ index on agent’s endpoints.

When port number is omited, it is assumed to be default SphinxQL IANA port (9312). However when portnumber is pointed, but invalid (say, port 70000), it will fail (skip) such agent.

In other words, you can point every single agent to one or more remote indexes, residing on one or more networked servers. There are absolutely no restrictions on the pointers. To point out a couple important things, the host can be localhost, and the remote index can be a distributed index in turn, all that is legal. That enables a bunch of very different usage modes:

  • sharding over multiple agent servers, and creating an arbitrary cluster topology;
  • sharding over multiple agent servers, mirrored for HA/LB (High Availability and Load Balancing) purposes;
  • sharding within localhost, to utilize multiple cores (however, it is simpler just to use multiple local indexes and dist_threads directive instead);

All agents are searched in parallel. An index list is passed verbatim to the remote agent. How exactly that list is searched within the agent (ie. sequentially or in parallel too) depends solely on the agent configuration (ie. dist_threads directive). Master has no remote control over that.

The value can additionally enumerate per agent options such as:

agent = address1:index-list[[ha_strategy=value] | [conn=value] | [blackhole=value]]

Example:

# config on box2
# sharding an index over 3 servers
agent = box2:9312:chunk2
agent = box3:9312:chunk3

# config on box2
# sharding an index over 3 servers
agent = box1:9312:chunk2
agent = box3:9312:chunk3

# config on box3
# sharding an index over 3 servers
agent = box1:9312:chunk2
agent = box2:9312:chunk3

# per agent options
agent = box1:9312:chunk1[ha_strategy=nodeads]
agent = box2:9312:chunk2[conn=pconn]
agent = test:9312:any[blackhole=1]
Agent mirrors

The syntax lets you define so-called agent mirrors that can be used interchangeably when processing a search query. Master server keeps track of mirror status (alive or dead) and response times, and does automatic failover and load balancing based on that. For example, this line:

agent = box1:9312|box2:9312|box3:9312:chunk2

declares that box1:9312, box2:9312, and box3:9312 all have an index called chunk2, and can be used as interchangeable mirrors. If any single of those servers go down, the queries will be distributed between the other two. When it gets back up, master will detect that and begin routing queries to all three boxes again.

Another way to define the mirrors is to explicitly specify the index list for every mirror:

agent = box1:9312:box1chunk2|box2:9312:box2chunk2

This works essentially the same as the previous example, but different index names will be used when querying different severs: box1chunk2 when querying box1:9312, and box2chunk when querying box2:9312.

By default, all queries are routed to the best of the mirrors. The best one is picked based on the recent statistics, as controlled by the ha_period_karma config directive. Master stores a number of metrics (total query count, error count, response time, etc) recently observed for every agent. It groups those by time spans, and karma is that time span length. The best agent mirror is then determined dynamically based on the last 2 such time spans. Specific algorithm that will be used to pick a mirror can be configured ha_strategy directive.

The karma period is in seconds and defaults to 60 seconds. Master stores up to 15 karma spans with per-agent statistics for instrumentation purposes (see SHOW AGENT STATUS statement). However, only the last 2 spans out of those are ever used for HA/LB logic.

When there are no queries, master sends a regular ping command every ha_ping_interval milliseconds in order to have some statistics and at least check, whether the remote host is still alive. ha_ping_interval defaults to 1000 msec. Setting it to 0 disables pings and statistics will only be accumulated based on actual queries.

Example:

# sharding index over 4 servers total
# in just 2 chunks but with 2 failover mirrors for each chunk
# box1, box2 carry chunk1 as local
# box3, box4 carry chunk2 as local

# config on box1, box2
agent = box3:9312|box4:9312:chunk2

# config on box3, box4
agent = box1:9312|box2:9312:chunk1

bigram_freq_words

A list of keywords considered “frequent” when indexing bigrams. Optional, default is empty.

Bigram indexing is a feature to accelerate phrase searches. When indexing, it stores a document list for either all or some of the adjacent words pairs into the index. Such a list can then be used at searching time to significantly accelerate phrase or sub-phrase matching.

Some of the bigram indexing modes (see bigram_index) require to define a list of frequent keywords. These are not to be confused with stopwords! Stopwords are completely eliminated when both indexing and searching. Frequent keywords are only used by bigrams to determine whether to index a current word pair or not.

bigram_freq_words lets you define a list of such keywords.

Example:

bigram_freq_words = the, a, you, i

bigram_index

Bigram indexing mode. Optional, default is none.

Bigram indexing is a feature to accelerate phrase searches. When indexing, it stores a document list for either all or some of the adjacent words pairs into the index. Such a list can then be used at searching time to significantly accelerate phrase or sub-phrase matching.

bigram_index controls the selection of specific word pairs. The known modes are:

  • all, index every single word pair. (NB: probably totally not worth it even on a moderately sized index, but added anyway for the sake of completeness.)
  • first_freq, only index word pairs where the first word is in a list of frequent words (see bigram_freq_words). For example, with bigram_freq_words = the, in, i, a, indexing “alone in the dark” text will result in “in the” and “the dark” pairs being stored as bigrams, because they begin with a frequent keyword (either “in” or “the” respectively), but “alone in” would not be indexed, because “in” is a second word in that pair.
  • both_freq, only index word pairs where both words are frequent. Continuing with the same example, in this mode indexing “alone in the dark” would only store “in the” (the very worst of them all from searching perspective) as a bigram, but none of the other word pairs.

For most usecases, both_freq would be the best mode, but your mileage may vary.

Example:

bigram_freq_words = both_freq

blend_chars

Blended characters list. Optional, default is empty.

Blended characters are indexed both as separators and valid characters. For instance, assume that & is configured as blended and AT&T occurs in an indexed document. Three different keywords will get indexed, namely “at&t”, treating blended characters as valid, plus “at” and “t”, treating them as separators.

Positions for tokens obtained by replacing blended characters with whitespace are assigned as usual, so regular keywords will be indexed just as if there was no blend_chars specified at all. An additional token that mixes blended and non-blended characters will be put at the starting position. For instance, if the field contents are “AT&T company” occurs in the very beginning of the text field, “at” will be given position 1, “t” position 2, “company” position 3, and “AT&T” will also be given position 1 (“blending” with the opening regular keyword). Thus, querying for either AT&T or just AT will match that document, and querying for “AT T” as a phrase also match it. Last but not least, phrase query for “AT&T company” will also match it, despite the position

Blended characters can overlap with special characters used in query syntax (think of T-Mobile or @twitter). Where possible, query parser will automatically handle blended character as blended. For instance, “hello @twitter” within quotes (a phrase operator) would handle @-sign as blended, because @-syntax for field operator is not allowed within phrases. Otherwise, the character would be handled as an operator. So you might want to escape the keywords.

Blended characters can be remapped, so that multiple different blended characters could be normalized into just one base form. This is useful when indexing multiple alternative Unicode codepoints with equivalent glyphs.

Example:

blend_chars = +, &, U+23
blend_chars = +, &->+

blend_mode

Blended tokens indexing mode. Optional, default is trim_none.

By default, tokens that mix blended and non-blended characters get indexed in there entirety. For instance, when both at-sign and an exclamation are in blend_chars, “@dude!” will get result in two tokens indexed: “@dude!” (with all the blended characters) and “dude” (without any). Therefore “@dude” query will not match it.

blend_mode directive adds flexibility to this indexing behavior. It takes a comma-separated list of options.

blend_mode = option [, option [, ...]]
option = trim_none | trim_head | trim_tail | trim_both | skip_pure

Options specify token indexing variants. If multiple options are specified, multiple variants of the same token will be indexed. Regular keywords (resulting from that token by replacing blended with whitespace) are always be indexed.

  • trim_none
  • Index the entire token.
  • trim_head
  • Trim heading blended characters, and index the resulting token.
  • trim_tail
  • Trim trailing blended characters, and index the resulting token.
  • trim_both
  • Trim both heading and trailing blended characters, and index the resulting token.
  • skip_pure
  • Do not index the token if it’s purely blended, that is, consists of blended characters only.

Returning to the “@dude!” example above, setting blend_mode = trim_head, trim_tail will result in two tokens being indexed, “@dude” and”dude!“. In this particular example, trim_both would have no effect, because trimming both blended characters results in”dude” which is already indexed as a regular keyword. Indexing “@U.S.A.” with trim_both (and assuming that dot is blended two) would result in “U.S.A” being indexed. Last but not least, skip_pure enables you to fully ignore sequences of blended characters only. For example, “one @@@ two” would be indexed exactly as “one two”, and match that as a phrase. That is not the case by default because a fully blended token gets indexed and offsets the second keyword position.

Default behavior is to index the entire token, equivalent to blend_mode = trim_none.

Example:

blend_mode = trim_tail, skip_pure

charset_table

Accepted characters table, with case folding rules. Optional, default value are latin and cyrillic characters.

charset_table is the main workhorse of Manticore tokenizing process, ie. the process of extracting keywords from document text or query text. It controls what characters are accepted as valid and what are not, and how the accepted characters should be transformed (eg. should the case be removed or not).

You can think of charset_table as of a big table that has a mapping for each and every of 100K+ characters in Unicode. By default, every character maps to 0, which means that it does not occur within keywords and should be treated as a separator. Once mentioned in the table, character is mapped to some other character (most frequently, either to itself or to a lowercase letter), and is treated as a valid keyword part.

The expected value format is a commas-separated list of mappings. Two simplest mappings simply declare a character as valid, and map a single character to another single character, respectively. But specifying the whole table in such form would result in bloated and barely manageable specifications. So there are several syntax shortcuts that let you map ranges of characters at once. The complete list is as follows:

  • A->a
  • Single char mapping, declares source char ‘A’ as allowed to occur within keywords and maps it to destination char ‘a’ (but does not declare ‘a’ as allowed).
  • A..Z->a..z
  • Range mapping, declares all chars in source range as allowed and maps them to the destination range. Does not declare destination range as allowed. Also checks ranges’ lengths (the lengths must be equal).
  • a
  • Stray char mapping, declares a character as allowed and maps it to itself. Equivalent to a->a single char mapping.
  • a..z
  • Stray range mapping, declares all characters in range as allowed and maps them to themselves. Equivalent to a..z->a..z range mapping.
  • A..Z/2
  • Checkerboard range map. Maps every pair of chars to the second char. More formally, declares odd characters in range as allowed and maps them to the even ones; also declares even characters as allowed and maps them to themselves. For instance, A..Z/2 is equivalent to A->B, B->B, C->D, D->D, …, Y->Z, Z->Z. This mapping shortcut is helpful for a number of Unicode blocks where uppercase and lowercase letters go in such interleaved order instead of contiguous chunks.

Control characters with codes from 0 to 31 are always treated as separators. Characters with codes 32 to 127, ie. 7-bit ASCII characters, can be used in the mappings as is. To avoid configuration file encoding issues, 8-bit ASCII characters and Unicode characters must be specified in U+xxx form, where ‘xxx’ is hexadecimal codepoint number. This form can also be used for 7-bit ASCII characters to encode special ones: eg. use U+20 to encode space, U+2E to encode dot, U+2C to encode comma.

Aliases “english” and “russian” are allowed at control character mapping.

Example:

# default are English and Russian letters
charset_table = 0..9, A..Z->a..z, _, a..z, \
    U+410..U+42F->U+430..U+44F, U+430..U+44F, U+401->U+451, U+451

# english charset defined with alias
charset_table = 0..9, english, _

dict

The keywords dictionary type. Known values are ‘crc’ and ‘keywords’. ‘crc’ is DEPRECATED. Use ‘keywords’ instead. Optional, default is ‘keywords’.

Keywords dictionary mode (dict=keywords), (greatly) reduces indexing impact and enable substring searches on huge collections. That mode is supported both for disk and RT indexes.

CRC dictionaries never store the original keyword text in the index. Instead, keywords are replaced with their control sum value (calculated using FNV64) both when searching and indexing, and that value is used internally in the index.

That approach has two drawbacks. First, there is a chance of control sum collision between several pairs of different keywords, growing quadratically with the number of unique keywords in the index. However, it is not a big concern as a chance of a single FNV64 collision in a dictionary of 1 billion entries is approximately 1:16, or 6.25 percent. And most dictionaries will be much more compact that a billion keywords, as a typical spoken human language has in the region of 1 to 10 million word forms.) Second, and more importantly, substring searches are not directly possible with control sums. Manticore alleviated that by pre-indexing all the possible substrings as separate keywords (see min_prefix_len, min_infix_len directives). That actually has an added benefit of matching substrings in the quickest way possible. But at the same time pre-indexing all substrings grows the index size a lot (factors of 3-10x and even more would not be unusual) and impacts the indexing time respectively, rendering substring searches on big indexes rather impractical.

Keywords dictionary fixes both these drawbacks. It stores the keywords in the index and performs search-time wildcard expansion. For example, a search for a ‘test*‘prefix could internally expand to ‘test|tests|testing’ query based on the dictionary contents. That expansion is fully transparent to the application, except that the separate per-keyword statistics for all the actually matched keywords would now also be reported.

For substring (infix) search extended wildcards may be used. Special symbols like ‘?’ and ‘%’ are supported along with substring (infix) search (e.g. “t?st“,”run%“,”abc*“). Note, however, these wildcards work only with dict=keywords, and not elsewhere.

Indexing with keywords dictionary should be 1.1x to 1.3x slower compared to regular, non-substring indexing - but times faster compared to substring indexing (either prefix or infix). Index size should only be slightly bigger that than of the regular non-substring index, with a 1..10% percent total difference. Regular keyword searching time must be very close or identical across all three discussed index kinds (CRC non-substring, CRC substring, keywords). Substring searching time can vary greatly depending on how many actual keywords match the given substring (in other words, into how many keywords does the search term expand). The maximum number of keywords matched is restricted by the expansion_limit directive.

Essentially, keywords and CRC dictionaries represent the two different trade-off substring searching decisions. You can choose to either sacrifice indexing time and index size in favor of top-speed worst-case searches (CRC dictionary), or only slightly impact indexing time but sacrifice worst-case searching time when the prefix expands into very many keywords (keywords dictionary).

Example:

dict = keywords

docinfo

Document attribute values (docinfo) storage mode. Optional, default is ‘