I did create and drop an index at some point while looking at this issue. But I definitely reran both of the queries (and explains) after the index was dropped, so I don't understand why there would be a difference between the inner and left query plans. (which were run back-to-back more than once) Anyways - I'll let you know if something similar happens again. Thanks, Jeremy Haile On Wed, 10 Jan 2007 14:22:35 -0500, "Tom Lane" <tgl@xxxxxxxxxxxxx> said: > "Jeremy Haile" <jhaile@xxxxxxxxxxx> writes: > > Another random idea - does PostgreSQL do any caching of query plans? > > Only if the client specifies it, either by PREPARE or the equivalent > protocol-level message. I dunno what client software you were using, > but I think few if any would PREPARE behind your back. Might be worth > checking into though, if you've eliminated autovacuum. > > Actually there's another possibility --- did you create any indexes on > the table in between? CREATE INDEX doesn't do a full stats update, but > it does count the rows and update pg_class.reltuples. But it's hard to > believe that'd have caused as big a rowcount shift as we see here ... > > regards, tom lane
