Re: No stats after promoting standby?

I'm pretty late on this, but as it seems you didn't get any answer...

2017-12-04 23:49 GMT+01:00 Don Seiler <don(at)seiler(dot)us>:

> On Mon, Dec 4, 2017 at 4:36 PM, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>
> wrote:
>
>> The optimizer stats are not lost on crash or promote actually; these are
>> stored in pg_statistic (not in the stats collector) and *are* part of
>> regular "data".
>>
>> ...
>>
>> I think it's pretty common misunderstanding -- it's not easy to see the
>> boundary between pg_statistic and pg_stat_* tables.
>
>
> Thanks for this. I thought I remembered being corrected on this before
> (probably on this very list) and just came to think of it at the end of my
> last message.
>
> So what, exactly ARE the pg_stat_* tables?
>

Activity statistics, collected by the stats collector process.

Is that the data stored in the files in stats_temp_directory?
>

Yes.

How do they differ from pg_statistic?
>
>
Those in pg_statistic are data statistics. They're used by the planner, and
collected by the ANALYZE SQL command.

I've found this blog post that seems to answer that question with a "Yes":
> https://blog.pgaddict.com/posts/the-two-kinds-of-stats-in-postgresql
>
>
+1

--
Guillaume.