Re: When was ANALYZE run in the past?

On Sat, 29 Nov 2014 15:27:07 -0500
Benjamin Rutt <rutt(dot)4(at)osu(dot)edu> wrote:

>I run autovacuum under
> a default configuration, but I suspect ANALYZE is not running frequently
> enough for my purposes (when I ran the above command on my table, it
> consistently returned 1.4 million for ~20 minutes straight; when I
> explicitly ran an ANALYZE command at that point (when I realized the
> estimate was not updating even every few minutes), the ANALYZE command took
> a few seconds, then the above command returned .7 million which matches
> what ‘select count(*)’ was returning). So I suspect ANALYZE is not running
> frequently enough or is stepping over my table for some reason.
>

Analyze is run by the autovacuum daemon, but you may be hitting the Cost-based Vacuum Delay if you deleted .7 million rows?

The documentation for postgresql 8.4 is no longer online, and things changed significantly since, so I'm not sure this applies exactly, but you can set table specific settings for the auto-vacuuming process; see :

http://www.postgresql.org/docs/current/static/routine-vacuuming.html#AUTOVACUUM

and

http://www.postgresql.org/docs/current/static/sql-createtable.html#SQL-CREATETABLE-STORAGE-PARAMETERS

--
Regards, Vincent Veyron

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