Merlin Moncure <mmoncure@xxxxxxxxx> writes: > If you are only interested in one or a very small number of cases of > 'permission', you can use an expression index to target constant > values: > "select ... from .... where ...... and (permission & mask = permission)" > create index foo_permission_xyz_idx on foo((64 & mask = 64)); > select * from foo where 64 & mask = 64; --indexed! A possibly more useful variant is to treat the permission condition as a partial index's WHERE condition. The advantage of that is that the index's actual content can be some other column, so that you can combine the permission check with a second indexable test. The index is still available for queries that don't use the other column, but it's more useful for those that do. regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
