Piotr Sulecki <Piotr.Sulecki@xxxxxxxxxxxxxxxxxxxxxxxxx> writes: > I have two really big tables, the problem is with one of them. The table > looks as follows: > ... > Indexes: > "pakiety_pkey" PRIMARY KEY, btree (pktid) > "pakiety_stid_received_idx" UNIQUE, btree (stid, received) > "pakiety_measured_idx" btree (measured) > "pakiety_received_idx" btree (received) > "pakiety_stid_measured_idx" btree (stid, measured) > trax=# explain select * from pakiety where stid = 234::smallint order by > received desc limit 1; The reason this won't use the (stid, received) index is that the requested sort order doesn't match that index. Try select * from pakiety where stid = 234::smallint order by stid desc, received desc limit 1; There is code in CVS tip to recognize that the equality constraint on stid allows the index to be considered as producing data ordered by received alone --- but no released version will make that deduction for you. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
