67 lines
2.4 KiB
Plaintext
67 lines
2.4 KiB
Plaintext
<!-- doc/src/sgml/btree-gin.sgml -->
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<sect1 id="btree-gin" xreflabel="btree_gin">
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<title>btree_gin — GIN operator classes with B-tree behavior</title>
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<indexterm zone="btree-gin">
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<primary>btree_gin</primary>
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</indexterm>
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<para>
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<filename>btree_gin</filename> provides GIN operator classes that
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implement B-tree equivalent behavior for the data types
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<type>int2</type>, <type>int4</type>, <type>int8</type>, <type>float4</type>,
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<type>float8</type>, <type>timestamp with time zone</type>,
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<type>timestamp without time zone</type>, <type>time with time zone</type>,
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<type>time without time zone</type>, <type>date</type>, <type>interval</type>,
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<type>oid</type>, <type>money</type>, <type>"char"</type>,
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<type>varchar</type>, <type>text</type>, <type>bytea</type>, <type>bit</type>,
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<type>varbit</type>, <type>macaddr</type>, <type>macaddr8</type>, <type>inet</type>,
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<type>cidr</type>, <type>uuid</type>, <type>name</type>, <type>bool</type>,
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<type>bpchar</type>, and all <type>enum</type> types.
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</para>
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<para>
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In general, these operator classes will not outperform the equivalent
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standard B-tree index methods, and they lack one major feature of the
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standard B-tree code: the ability to enforce uniqueness. However,
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they are useful for GIN testing and as a base for developing other
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GIN operator classes. Also, for queries that test both a GIN-indexable
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column and a B-tree-indexable column, it might be more efficient to create
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a multicolumn GIN index that uses one of these operator classes than to create
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two separate indexes that would have to be combined via bitmap ANDing.
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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 id="btree-gin-example-usage">
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<title>Example Usage</title>
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<programlisting>
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CREATE TABLE test (a int4);
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-- create index
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CREATE INDEX testidx ON test USING GIN (a);
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-- query
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SELECT * FROM test WHERE a < 10;
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</programlisting>
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</sect2>
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<sect2 id="btree-gin-authors">
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<title>Authors</title>
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<para>
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Teodor Sigaev (<email>teodor@stack.net</email>) and
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Oleg Bartunov (<email>oleg@sai.msu.su</email>). See
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<ulink url="http://www.sai.msu.su/~megera/oddmuse/index.cgi/Gin"></ulink>
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for additional information.
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</para>
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</sect2>
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</sect1>
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