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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>12.7. Configuration Example</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="textsearch-dictionaries.html" title="12.6. Dictionaries" /><link rel="next" href="textsearch-debugging.html" title="12.8. Testing and Debugging Text Search" /></head><body><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">12.7. Configuration Example</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="textsearch-dictionaries.html" title="12.6. Dictionaries">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="textsearch.html" title="Chapter 12. Full Text Search">Up</a></td><th width="60%" align="center">Chapter 12. Full Text Search</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 11.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="textsearch-debugging.html" title="12.8. Testing and Debugging Text Search">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="TEXTSEARCH-CONFIGURATION"><div class="titlepage"><div><div><h2 class="title" style="clear: both">12.7. Configuration Example</h2></div></div></div><p>
A text search configuration specifies all options necessary to transform a
document into a <code class="type">tsvector</code>: the parser to use to break text
into tokens, and the dictionaries to use to transform each token into a
lexeme. Every call of
<code class="function">to_tsvector</code> or <code class="function">to_tsquery</code>
needs a text search configuration to perform its processing.
The configuration parameter
<a class="xref" href="runtime-config-client.html#GUC-DEFAULT-TEXT-SEARCH-CONFIG">default_text_search_config</a>
specifies the name of the default configuration, which is the
one used by text search functions if an explicit configuration
parameter is omitted.
It can be set in <code class="filename">postgresql.conf</code>, or set for an
individual session using the <code class="command">SET</code> command.
</p><p>
Several predefined text search configurations are available, and
you can create custom configurations easily. To facilitate management
of text search objects, a set of <acronym class="acronym">SQL</acronym> commands
is available, and there are several <span class="application">psql</span> commands that display information
about text search objects (<a class="xref" href="textsearch-psql.html" title="12.10. psql Support">Section 12.10</a>).
</p><p>
As an example we will create a configuration
<code class="literal">pg</code>, starting by duplicating the built-in
<code class="literal">english</code> configuration:
</p><pre class="programlisting">
CREATE TEXT SEARCH CONFIGURATION public.pg ( COPY = pg_catalog.english );
</pre><p>
</p><p>
We will use a PostgreSQL-specific synonym list
and store it in <code class="filename">$SHAREDIR/tsearch_data/pg_dict.syn</code>.
The file contents look like:
</p><pre class="programlisting">
postgres pg
pgsql pg
postgresql pg
</pre><p>
We define the synonym dictionary like this:
</p><pre class="programlisting">
CREATE TEXT SEARCH DICTIONARY pg_dict (
TEMPLATE = synonym,
SYNONYMS = pg_dict
);
</pre><p>
Next we register the <span class="productname">Ispell</span> dictionary
<code class="literal">english_ispell</code>, which has its own configuration files:
</p><pre class="programlisting">
CREATE TEXT SEARCH DICTIONARY english_ispell (
TEMPLATE = ispell,
DictFile = english,
AffFile = english,
StopWords = english
);
</pre><p>
Now we can set up the mappings for words in configuration
<code class="literal">pg</code>:
</p><pre class="programlisting">
ALTER TEXT SEARCH CONFIGURATION pg
ALTER MAPPING FOR asciiword, asciihword, hword_asciipart,
word, hword, hword_part
WITH pg_dict, english_ispell, english_stem;
</pre><p>
We choose not to index or search some token types that the built-in
configuration does handle:
</p><pre class="programlisting">
ALTER TEXT SEARCH CONFIGURATION pg
DROP MAPPING FOR email, url, url_path, sfloat, float;
</pre><p>
</p><p>
Now we can test our configuration:
</p><pre class="programlisting">
SELECT * FROM ts_debug('public.pg', '
PostgreSQL, the highly scalable, SQL compliant, open source object-relational
database management system, is now undergoing beta testing of the next
version of our software.
');
</pre><p>
</p><p>
The next step is to set the session to use the new configuration, which was
created in the <code class="literal">public</code> schema:
</p><pre class="screen">
=> \dF
List of text search configurations
Schema | Name | Description
---------+------+-------------
public | pg |
SET default_text_search_config = 'public.pg';
SET
SHOW default_text_search_config;
default_text_search_config
----------------------------
public.pg
</pre><p>
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