Miernik <[EMAIL PROTECTED]> writes: > miernik=> EXPLAIN UPDATE cnts SET p0 = FALSE WHERE uid IN (SELECT uid FROM > alog WHERE pid = 3452654 AND o = 1); > QUERY PLAN > ----------------------------------------------------------------------------------------------- > Nested Loop IN Join (cost=0.00..3317.34 rows=1 width=44) > -> Seq Scan on cnts (cost=0.00..36.00 rows=2000 width=44) > -> Index Scan using alog_uid_idx on alog (cost=0.00..296.95 rows=1 > width=4) > Index Cond: ((alog.uid)::integer = (cnts.uid)::integer) > Filter: ((alog.pid = 3452654::numeric) AND (alog.o = 1::numeric)) > (5 rows)
> But if I give him only the inner part, it makes reasonable assumptions > and runs OK: What's the results for explain select * from cnts, alog where alog.uid = cnts.uid ? If necessary, turn off enable_hashjoin and enable_mergejoin so we can see a comparable plan. I'm suspecting it thinks the condition on uid is more selective than the one on the other index. regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance