Re: Extremely irregular query performance
От
Tom Lane
Тема
Re: Extremely irregular query performance
Дата
Msg-id
480.1137036235@sss.pgh.pa.us
Ответ на
Re: Extremely irregular query performance (Jean-Philippe Côté)
Список
Дерево обсуждения
Extremely irregular query performance Jean-Philippe Côté<jean-philippe.cote@crt.umontreal.ca>
Re: Extremely irregular query performance Scott Marlowe <smarlowe@g2switchworks.com>
Re: Extremely irregular query performance Tom Lane <tgl@sss.pgh.pa.us>
Re: Extremely irregular query performance Jean-Philippe Côté<jean-philippe.cote@crt.umontreal.ca>
Re: Extremely irregular query performance Mark Lewis <mark.lewis@mir3.com>
Re: Extremely irregular query performance Tom Lane <tgl@sss.pgh.pa.us>
Re: Extremely irregular query performance Simon Riggs <simon@2ndquadrant.com>
Re: Extremely irregular query performance Kenneth Marshall <ktm@it.is.rice.edu>
Re: Extremely irregular query performance Jean-Philippe Cote <jean-philippe.cote@crt.umontreal.ca>
Re: Extremely irregular query performance Kenneth Marshall <ktm@it.is.rice.edu>
Re: Extremely irregular query performance Bruce Momjian <pgman@candle.pha.pa.us>
Re: Extremely irregular query performance Bruce Momjian <pgman@candle.pha.pa.us>
Re: Extremely irregular query performance Tom Lane <tgl@sss.pgh.pa.us>
Re: Extremely irregular query performance Bruce Momjian <pgman@candle.pha.pa.us>
=?iso-8859-1?Q?Jean-Philippe_C=F4t=E9?= writes: > Thanks a lot for this info, I was indeed exceeding the genetic > optimizer's threshold. Now that it is turned off, I get > a very stable response time of 435ms (more or less 5ms) for > the same query. It is about three times slower than the best > I got with the genetic optimizer on, but the overall average > is much lower. Hmm. It would be interesting to use EXPLAIN ANALYZE to confirm that the plan found this way is the same as the best plan found by GEQO, and the extra couple hundred msec is the price you pay for the exhaustive plan search. If GEQO is managing to find a plan better than the regular planner then we need to look into why ... regards, tom lane
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