Re: Extremely irregular query performance
От | Bruce Momjian |
---|---|
Тема | Re: Extremely irregular query performance |
Дата | |
Msg-id | 200601140423.k0E4NX019385@candle.pha.pa.us обсуждение исходный текст |
Ответ на | Re: Extremely irregular query performance (Jean-Philippe Cote <jean-philippe.cote@crt.umontreal.ca>) |
Список | pgsql-performance |
Jean-Philippe Cote wrote: > > > Can I actully know whether a given plan is excuted with GEQO on ? > In other words, if I launch 'explain <query>', I'll get a given plan, but if I re-launch > the <query> (withtout the 'explain' keyword), could I get a different > plan given that GEQO induces some randomness ? > > >Is it the plan that is different in the fastest case with GEQO or is it > >the time needed to plan that is causing the GEQO to beat the exhaustive > >search? Yes, is it likely that when using GEQO you would get a different plan each time, so running it with and without EXPLAIN would produce different plans. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073
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