PostgreSQL 8.4.9 Documentation
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# F.3. btree_gin

`btree_gin` provides sample GIN operator classes that implement B-Tree equivalent behavior for the data types `int2`, `int4`, `int8`, `float4`, `float8`, `timestamp with time zone`, `timestamp without time zone`, `time with time zone`, `time without time zone`, `date`, `interval`, `oid`, `money`, `"char"`, `varchar`, `text`, `bytea`, `bit`, `varbit`, `macaddr`, `inet`, and `cidr`.

In general, these operator classes will not outperform the equivalent standard btree index methods, and they lack one major feature of the standard btree code: the ability to enforce uniqueness. However, they are useful for GIN testing and as a base for developing other GIN operator classes. Also, for queries that test both a GIN-indexable column and a btree-indexable column, it might be more efficient to create a multi-column GIN index that uses one of these opclasses than to create two separate indexes that would have to be combined via bitmap ANDing.

## F.3.1. Example usage

    CREATE TABLE test (a int4);
    -- create index
    CREATE INDEX testidx ON test USING gin (a);
    -- query
    SELECT * FROM test WHERE a < 10;

## F.3.2. Authors

Teodor Sigaev (`<teodor@stack.net>`) and Oleg Bartunov (`<oleg@sai.msu.su>`). See http://www.sai.msu.su/~megera/oddmuse/index.cgi/Gin for additional information.

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