Hello, I'm not saying this change shouldn't be made, but make sure you keep in mind the original reason/issue that changed from "status < 2" to "status in (0,1)" in the first place:
http://mailman.fastxs.net/pipermail/dbmail-dev/2005-October/007594.html and http://www.dbmail.org/mantis/view.php?id=278 We saw a huge performance improvement ourselves, using pop3. That's was on postgres 7.4, and maybe/probably things have improved with later versions. Also note in the single function that was causing us problems, you could completely eliminate the status comparison with basically no adverse effect (so maybe eliminate it there, and change it to a < 2 comparison everywhere else if that needs done?). Jesse On Fri, 2006-10-20 at 00:05 -0700, Aaron Stone wrote: > Ok, I think we should change the query in db_getmailbox_count to be < 2 > because the plan really is a lot less expensive than IN (0, 1). I know > this was a thread/bug we had a week or two ago, but it popped into my > head today that maybe the planner was guessing the IN (0, 1) meant the > same at < 2. It doesn't, and even on Pg 8, it's still more expensive. > > Aaron > > dbmail=# explain select message_idnr from dbmail_messages where > mailbox_idnr = 1 and status in (0, 1) order by message_idnr asc; > QUERY > PLAN > ------------------------------------------------------------------------------------------------------------------ > Sort (cost=9.67..9.67 rows=1 width=8) > Sort Key: message_idnr > -> Index Scan using dbmail_messages_8, dbmail_messages_8 on > dbmail_messages (cost=0.00..9.66 rows=1 width=8) > Index Cond: (((mailbox_idnr = 1) AND (status = 0)) OR > ((mailbox_idnr = 1) AND (status = 1))) > Filter: ((mailbox_idnr = 1) AND ((status = 0) OR (status = 1))) > (5 rows) > > dbmail=# explain select message_idnr from dbmail_messages where > mailbox_idnr = 1 and status < 2 order by message_idnr asc; > QUERY > PLAN > ----------------------------------------------------------------------------------------------- > Sort (cost=8.31..8.31 rows=2 width=8) > Sort Key: message_idnr > -> Index Scan using dbmail_messages_8 on dbmail_messages > (cost=0.00..8.30 rows=2 width=8) > Index Cond: ((mailbox_idnr = 1) AND (status < 2)) > > > _______________________________________________ > Dbmail-dev mailing list > Dbmail-dev@dbmail.org > http://twister.fastxs.net/mailman/listinfo/dbmail-dev -- Jesse Norell - [EMAIL PROTECTED] Kentec Communications, Inc.
