Re: 8.2.4 serious slowdown
От | Sim Zacks |
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Тема | Re: 8.2.4 serious slowdown |
Дата | |
Msg-id | fm76ju$11rv$1@news.hub.org обсуждение исходный текст |
Ответ на | Re: 8.2.4 serious slowdown (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: 8.2.4 serious slowdown
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Список | pgsql-general |
I changed it to "where f.commited is not true" and the query now takes 1 second as opposed to 60. (much faster then the 3 seconds it took on 8.0.1, which could also be because of the coalesce there) Is it considered better practice (or more efficient) to always use (x is not or x=value) instead of coalesce? Or does it make more sense to turn on the option "transform_null_equals"? Thank you much Sim > I assume that the original query is something along the lines of > > d left join f on (...) where coalesce(f.commited, false) = false > > > In the meantime, Sim would probably have better luck if he restructured > this particular clause in some other way, say > > where f.commited is not true > or > where f.commited = false or f.commited is null > > Note also that he really ought to move up to 8.2.6, as 8.2.4 is not > very sane about what IS NULL means for a left join's result. > > regards, tom lane > > ---------------------------(end of broadcast)--------------------------- > TIP 6: explain analyze is your friend >
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