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This allows these modules to be installed into a database without superuser privileges (assuming that the DBA or sysadmin has installed the module's files in the expected place). You only need CREATE privilege on the current database, which by default would be available to the database owner. The following modules are marked trusted: btree_gin btree_gist citext cube dict_int earthdistance fuzzystrmatch hstore hstore_plperl intarray isn jsonb_plperl lo ltree pg_trgm pgcrypto seg tablefunc tcn tsm_system_rows tsm_system_time unaccent uuid-ossp In the future we might mark some more modules trusted, but there seems to be no debate about these, and on the whole it seems wise to be conservative with use of this feature to start out with. Discussion: https://postgr.es/m/32315.1580326876@sss.pgh.pa.us
92 lines
2.6 KiB
Plaintext
92 lines
2.6 KiB
Plaintext
<!-- doc/src/sgml/dict-int.sgml -->
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<sect1 id="dict-int" xreflabel="dict_int">
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<title>dict_int</title>
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<indexterm zone="dict-int">
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<primary>dict_int</primary>
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</indexterm>
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<para>
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<filename>dict_int</filename> is an example of an add-on dictionary template
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for full-text search. The motivation for this example dictionary is to
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control the indexing of integers (signed and unsigned), allowing such
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numbers to be indexed while preventing excessive growth in the number of
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unique words, which greatly affects the performance of searching.
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</para>
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<para>
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This module is considered <quote>trusted</quote>, that is, it can be
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installed by non-superusers who have <literal>CREATE</literal> privilege
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on the current database.
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</para>
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<sect2>
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<title>Configuration</title>
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<para>
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The dictionary accepts two options:
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</para>
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<itemizedlist>
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<listitem>
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<para>
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The <literal>maxlen</literal> parameter specifies the maximum number of
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digits allowed in an integer word. The default value is 6.
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</para>
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</listitem>
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<listitem>
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<para>
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The <literal>rejectlong</literal> parameter specifies whether an overlength
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integer should be truncated or ignored. If <literal>rejectlong</literal> is
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<literal>false</literal> (the default), the dictionary returns the first
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<literal>maxlen</literal> digits of the integer. If <literal>rejectlong</literal> is
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<literal>true</literal>, the dictionary treats an overlength integer as a stop
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word, so that it will not be indexed. Note that this also means that
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such an integer cannot be searched for.
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</para>
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</listitem>
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</itemizedlist>
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</sect2>
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<sect2>
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<title>Usage</title>
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<para>
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Installing the <literal>dict_int</literal> extension creates a text search
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template <literal>intdict_template</literal> and a dictionary <literal>intdict</literal>
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based on it, with the default parameters. You can alter the
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parameters, for example
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<programlisting>
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mydb# ALTER TEXT SEARCH DICTIONARY intdict (MAXLEN = 4, REJECTLONG = true);
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ALTER TEXT SEARCH DICTIONARY
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</programlisting>
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or create new dictionaries based on the template.
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</para>
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<para>
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To test the dictionary, you can try
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<programlisting>
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mydb# select ts_lexize('intdict', '12345678');
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ts_lexize
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-----------
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{123456}
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</programlisting>
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but real-world usage will involve including it in a text search
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configuration as described in <xref linkend="textsearch"/>.
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That might look like this:
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<programlisting>
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ALTER TEXT SEARCH CONFIGURATION english
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ALTER MAPPING FOR int, uint WITH intdict;
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</programlisting>
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</para>
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</sect2>
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</sect1>
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