Re: 8.2rc1 (much) slower than 8.2dev?
От | Arjen van der Meijden |
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Тема | Re: 8.2rc1 (much) slower than 8.2dev? |
Дата | |
Msg-id | 45744FAA.20603@tweakers.net обсуждение исходный текст |
Ответ на | Re: 8.2rc1 (much) slower than 8.2dev? (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: 8.2rc1 (much) slower than 8.2dev?
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Список | pgsql-performance |
Tom Lane wrote: > Arjen van der Meijden <acmmailing@tweakers.net> writes: >> I'll run another analyze on the database to see if that makes any >> difference, but after that I'm not sure what to check first to figure >> out where things go wrong? > > Look for changes in plans? Yeah, there are a few number of small changes in plans and costs estimated. I've a large list of queries executed against both databases, and I haven't seen any differences in row-estimates, so the analyze's have yielded similar enough results. I'm not sure whether some of the changes are for better or worse, you can probably spot that a bit faster than I can. I saw a few index scans replaced by seq scans (on small tables), all index scans seem to have doubled in cost? And I saw a few bitmap scans in stead of normal index scans and more such small changes. But not so small if you execute a hundreds of thousands of those queries. Since I'd rather not send the entire list of queries to the entire world, is it OK to send both explain analyze-files to you off list? Best regards, Arjen
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