Re: About vacuuming
От | Jason Priebe |
---|---|
Тема | Re: About vacuuming |
Дата | |
Msg-id | 002701c1c12c$bda762f0$02a8a8c0@priebe обсуждение исходный текст |
Ответ на | Re: About vacuuming ("Tim Barnard" <tbarnard@povn.com>) |
Список | pgsql-general |
Just to further this a bit -- running or not running VACUUM ANALYZE can have huge performance implications. Some queries were taking extremely long times to execute on our database. Running a VACUUM ANALYZE (which had not ever been done on this database, despite having inserted hundreds of thousands of records) led to at least an order of magnitude improvement in the performance of the query. Basically, the optimizer was working with no good information before the VACUUM ANALYZE; now it's got all kinds of statistics to improve its optimization. This particular query was joining about 5 tables, so there were lots of opportunities for optimization. Jason Priebe Mi-Co http://www.mi-corporation.com/ > -----Original Message----- > From: pgsql-general-owner@postgresql.org > [mailto:pgsql-general-owner@postgresql.org] On Behalf Of Tim Barnard > > Vacuum analyze updates the statistics that the db uses to > determine various > query plans, so I'd always run it as vacuum analyze, rather than just > vacuum. > > ----- Original Message ----- > From: "Peter Peltonen" <peter.peltonen@fivetec.com> > > > Is vacuum --analyze for just providing information or does > it somehow > > store it's info for postgresql's use (in other words: > should I run it too, > > and if so, should I do it before or after the real vacuum?). > >
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