Re: Query Plan
От | Gregory Stark |
---|---|
Тема | Re: Query Plan |
Дата | |
Msg-id | 874pk96zhk.fsf@oxford.xeocode.com обсуждение исходный текст |
Ответ на | Query Plan ("Radhika Sambamurti" <radhika@88thstreet.com>) |
Список | pgsql-sql |
"Radhika Sambamurti" <radhika@88thstreet.com> writes: > When I run the query with combination of FirmClearingID & status the run > times are approx 3700ms. > But when I add tradedate ie date_trunc('day', tradedate) = '20070703' the > run time becomes a horrendous 19631.958 ms. I'm not really able to make heads or tails of your plans without the query. But any where clause of the form date_trunc('...',col)='...' will always generate crappy plans. And it looks like you already have expressions of that form in the view even in the one which you label "without date_trunc". Instead try to write a where clause that the database can understand the end points of. Something like (col >= '20070703' and col < '20070704'). That's something the database can apply a normal index to and also something it can have a chance at guessing how many rows will fit. -- Gregory Stark EnterpriseDB http://www.enterprisedb.com
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