Jim Crate <jimcfl@xxxxxxxxx> writes: > My question is why does it do a seq scan when it flattens this > subquery into a JOIN? Because it thinks there will be 3783 rows out of the msg scan, which if true would make your desired nestloop join a serious loser. You need to see about getting that estimate to be off by less than three orders of magnitude. Possibly raising the stats target on emsg_messages would help. I'd also try converting the inner NOT IN into a NOT EXISTS, just to see if that makes the estimate any better. Using something newer than 9.0.2 might help too, as we fixed some outer-join estimation bugs a few months ago. 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
