Re: GiST index on INT8, possible bug in query planner? - Mailing list pgsql-general

Jan Behrens <jbe@public-software-group.org> writes:
> However, the GiST index seems not to work as expected by me when
> 64-bit integers are involved. I tried to create a minimal
> proof-of-concept to demonstrate this. Consider the following setup:
> CREATE TABLE test8_gist (id SERIAL4, ctx INT8);
> CREATE INDEX ON test8_gist USING gist (ctx, id);
> EXPLAIN SELECT * FROM test8_gist WHERE ctx = 1 AND id = 2;
> -- uses Index Cond: (id = 2)
> The query planning for the select on table "test8_gist" does not
> include "ctx" in the "Index Cond".

Probably it would if you'd written "WHERE ctx = 1::int8".  Without
the cast, what you'll have is "int8 = int4", and I suspect that
btree_gist doesn't include cross-type operators in its opclasses.

            regards, tom lane