"Mike Biamonte" <mike@xxxxxxxxx> writes: > The queries I need to run on my 200 million transactions are relatively > simple: > select month, count(distinct(cardnum)) count(*), sum(amount) from > transactions group by month; count(distinct) is not "relatively simple", and the current implementation isn't especially efficient. Can you avoid that construct? Assuming that "month" means what it sounds like, the above would result in running twelve parallel sort/uniq operations, one for each month grouping, to eliminate duplicates before counting. You've got sortmem set high enough to blow out RAM in that scenario ... regards, tom lane
