Richard Huxton <dev@xxxxxxxxxxxx> writes: > If you connect via psql and then (as root, in another terminal) do: > ps auxw | grep postgres > you should see the backend that corresponds to your psql connection. > strace -p <pid> > should then show system calls as they are executed (assuming you have it > installed). Execute the explain, and see what is output. > Mine flies past, but is composed almost entirely of "gettimeofday" calls > (10,000 of them) apart from at the very end where we get some write and > send/recv calls (to print the explain results). I've heard of some > people having slow "gettimeofday" calls, but not on linux. On the other > hand, that seems to be the main difference between strace output with > "not in" compared to "in". AFAICT Sergey is complaining about the speed of EXPLAIN, *not* EXPLAIN ANALYZE. There'd only be a lot of gettimeofday calls in an EXPLAIN ANALYZE test. The whole thing doesn't make a lot of sense to me either. All the slowdown explanations I can think of would apply as much or more to the IN case... regards, tom lane -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
