Miernik <public@xxxxxxxxxxxxxxxxxxx> 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
