59 lines
1.9 KiB
Plaintext
59 lines
1.9 KiB
Plaintext
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<!-- $PostgreSQL: pgsql/doc/src/sgml/btree-gin.sgml,v 1.1 2009/03/25 23:20:01 tgl Exp $ -->
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<sect1 id="btree-gin">
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<title>btree_gin</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</> provides sample GIN operator classes that
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implement B-Tree equivalent behavior for the data types
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<type>int2</>, <type>int4</>, <type>int8</>, <type>float4</>,
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<type>float8</>, <type>timestamp with time zone</>,
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<type>timestamp without time zone</>, <type>time with time zone</>,
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<type>time without time zone</>, <type>date</>, <type>interval</>,
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<type>oid</>, <type>money</>, <type>"char"</>,
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<type>varchar</>, <type>text</>, <type>bytea</>, <type>bit</>,
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<type>varbit</>, <type>macaddr</>, <type>inet</>, and <type>cidr</>.
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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 btree index methods, and they lack one major feature of the
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standard btree 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 btree-indexable column, it might be more efficient to create
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a multi-column GIN index that uses one of these opclasses 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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<sect2>
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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>
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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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