Re: When was ANALYZE run in the past?

On 11/30/2014 06:55 AM, Vincent Veyron wrote:
> 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

FYI the docs are still online. So for example, if you go to the above
page and look at the top of the page you will see links for
documentation going back to 7.2 and forward to devel. Clicking on the
link will take you to the equivalent page in the respective version.
This is one of the many gems of the Postgres docs.

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

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com