Re: template0 needing vacuum freeze?

On Mon, May 18, 2020 at 1:40 AM Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at>
wrote:

>
> Did you see any weird messages when you vacuumed "template0"?
>

No.

> Did "datfrozenxid" shrink after the operation?
>
> "foo_db" seems to be the bigger problem.

Perhaps autovacuum never handled "template0" because it concluded (rightly)
> that
> it has to deal with "foo_db" first.
>

Yes this DB had a table in it that had been autovacuuming since Feb 2. It's
age is half way to wraparound so I'm in the middle of a manual VACUUM
FREEZE on it. I'd be interested in knowing if that prevents template0 from
autovacuuming itself. There are no other autovacuum jobs running.

>
> > I can say that these DB
> > has previously been altered for locale changes as well.
>
> Would you care to explain that? You changed "template0"? How?
>

It was changed before my time here to change the encoding from LATIN1 to
UTF manually. One of the fun treats I'm working to correct as I also
prepare these for upgrade to PG12.

What are your non-default autovacuum settings? Perhaps you should speed up
> autovacuum
> by reducing "autovacuum_vacuum_cost_delay" to 2ms or less, and by
> increasing
> "maintenance_work_mem".
>

All autovacuum settings on this DB are default. Cost delay is at the
default 20ms. maintenance_work_mem I've already increased to 512MB (this VM
has 8GB RAM).

--
Don Seiler
www.seiler.us