Re: PG12 autovac issues

Hi,

On 2020-03-23 16:31:21 -0500, Justin King wrote:
> This is occurring in our environment right now (started about 30 min
> ago). Here 's the latest logs (grepped by vacuum):
>
> Mar 23 20:54:16 cowtn postgres[15569]: [12-1] 2020-03-23 20:54:16.542
> GMT [15569] LOG: automatic vacuum of table "feedi.production.tita":
> index scans: 1
> Mar 23 20:54:27 cowtn postgres[15654]: [8-1] 2020-03-23 20:54:27.964
> GMT [15654] LOG: automatic vacuum of table
> "feedi.production.distributed_virtual_schedule": index scans: 1

Hm, unfortunately you've cut off the details in the subsequent
lines. There's a few newlines in the output. Any chance you could
re-post with those included?

> > > > I wonder if what might be happening is that we're somehow missed/failed
> > > > to update relfrozenxid and/or datfrozenxid. If you manually vacuum some
> > > > table in the oldest database, but that is *NOT* the oldest table itself,
> > > > does the problem "resolve" itself?
>
> postgres=# SELECT datname
> , age(datfrozenxid)
> , current_setting('autovacuum_freeze_max_age')
> FROM pg_database;
> datname | age | current_setting
> -----------+-----------+-----------------
> postgres | 202375735 | 200000000
> template1 | 202345459 | 200000000
> template0 | 132459914 | 200000000
> feedi | 132459914 | 200000000
> (4 rows)

Can you show the oldest tables in 'feedi'? Or, hm, actually, could you
just post the result of all the queries from the "What is:" section in
https://postgr.es/m/20200323162303.s7ay5hjdvimtkz6u%40alap3.anarazel.de

> Since this is occurring right now, what else would be useful to
> capture? You'd asked about a GDB -- do you want that of the main
> process or the autovac worker?

Unless you can give me gdb access directly, I don't yet have enough data
to suggest what exactly we would want to analyze with gdb in your case.

It'd be helpful if you could change log_min_messages to DEBUG1 and
reload the configuration (not restart!).

Greetings,

Andres Freund