©
Dokumen ini menggunakan Manual laman web PHP Cina Lepaskan
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 B-tree index methods, and they lack one major feature of the standard B-tree 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 B-tree-indexable column, it might be more efficient to create a multicolumn GIN index that uses one of these operator classes than to create two separate indexes that would have to be combined via bitmap ANDing.
CREATE TABLE test (a int4); -- create index CREATE INDEX testidx ON test USING gin (a); -- query SELECT * FROM test WHERE a < 10;
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.