Re: [patch] BUG #15005: ANALYZE can make pg_class.reltuplesinaccurate.
От | David Gould |
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Тема | Re: [patch] BUG #15005: ANALYZE can make pg_class.reltuplesinaccurate. |
Дата | |
Msg-id | 20180304191918.39e95382@engels обсуждение исходный текст |
Ответ на | Re: [patch] BUG #15005: ANALYZE can make pg_class.reltuples inaccurate. (Jeff Janes <jeff.janes@gmail.com>) |
Ответы |
Re: [patch] BUG #15005: ANALYZE can make pg_class.reltuples inaccurate.
Re: [patch] BUG #15005: ANALYZE can make pg_class.reltuplesinaccurate. |
Список | pgsql-hackers |
On Sun, 4 Mar 2018 07:49:46 -0800 Jeff Janes <jeff.janes@gmail.com> wrote: > I don't see how it could have caused the problem in the first place. In > your demonstration case, you had to turn off autovac in order to get it to > happen, and then when autovac is turned back on, it is all primed for an > autovac to launch, go through, touch almost all of the pages, and fix it > for you. How did your original table get into a state where this wouldn't > happen? One more way for this to happen, vacuum was including the dead tuples in the estimate in addition to the live tuples. This is a separate bug that tends to aggravate the one I'm trying to fix. See the thread re BUG #15005 at: https://www.postgresql.org/message-id/16db4468-edfa-830a-f921-39a50498e77e%402ndquadrant.com > It seems to me that VACUUM and ANALYZE somewhat disagree on what exactly > reltuples means. VACUUM seems to be thinking that > > reltuples = live + dead > > while ANALYZE apparently believes that > > reltuples = live There is a patch for this one from Tomas Vondra/Tom Lane that I hope it will land in the next set of releases. -dg -- David Gould daveg@sonic.net If simplicity worked, the world would be overrun with insects.
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