postgresql/doc/src/sgml/dict-int.sgml
Tom Lane eb67623c96 Mark some contrib modules as "trusted".
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
2020-02-13 15:02:35 -05:00

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<!-- doc/src/sgml/dict-int.sgml -->
<sect1 id="dict-int" xreflabel="dict_int">
<title>dict_int</title>
<indexterm zone="dict-int">
<primary>dict_int</primary>
</indexterm>
<para>
<filename>dict_int</filename> is an example of an add-on dictionary template
for full-text search. The motivation for this example dictionary is to
control the indexing of integers (signed and unsigned), allowing such
numbers to be indexed while preventing excessive growth in the number of
unique words, which greatly affects the performance of searching.
</para>
<para>
This module is considered <quote>trusted</quote>, that is, it can be
installed by non-superusers who have <literal>CREATE</literal> privilege
on the current database.
</para>
<sect2>
<title>Configuration</title>
<para>
The dictionary accepts two options:
</para>
<itemizedlist>
<listitem>
<para>
The <literal>maxlen</literal> parameter specifies the maximum number of
digits allowed in an integer word. The default value is 6.
</para>
</listitem>
<listitem>
<para>
The <literal>rejectlong</literal> parameter specifies whether an overlength
integer should be truncated or ignored. If <literal>rejectlong</literal> is
<literal>false</literal> (the default), the dictionary returns the first
<literal>maxlen</literal> digits of the integer. If <literal>rejectlong</literal> is
<literal>true</literal>, the dictionary treats an overlength integer as a stop
word, so that it will not be indexed. Note that this also means that
such an integer cannot be searched for.
</para>
</listitem>
</itemizedlist>
</sect2>
<sect2>
<title>Usage</title>
<para>
Installing the <literal>dict_int</literal> extension creates a text search
template <literal>intdict_template</literal> and a dictionary <literal>intdict</literal>
based on it, with the default parameters. You can alter the
parameters, for example
<programlisting>
mydb# ALTER TEXT SEARCH DICTIONARY intdict (MAXLEN = 4, REJECTLONG = true);
ALTER TEXT SEARCH DICTIONARY
</programlisting>
or create new dictionaries based on the template.
</para>
<para>
To test the dictionary, you can try
<programlisting>
mydb# select ts_lexize('intdict', '12345678');
ts_lexize
-----------
{123456}
</programlisting>
but real-world usage will involve including it in a text search
configuration as described in <xref linkend="textsearch"/>.
That might look like this:
<programlisting>
ALTER TEXT SEARCH CONFIGURATION english
ALTER MAPPING FOR int, uint WITH intdict;
</programlisting>
</para>
</sect2>
</sect1>