Re: how to shrink pg_attribute table in some database

Thanks,

as we understand there is a lack of autovacuum max workers in
postgresql.conf.

One question more, what impact would be on streaming replication? Will full
vacuum create extra wal files during full vacuum?

Thanks a lot

2018-03-26 18:24 GMT+03:00 hubert depesz lubaczewski <depesz(at)depesz(dot)com>:

> On Mon, Mar 26, 2018 at 05:33:19PM +0300, Artem Tomyuk wrote:
> > Can't, it generates huge IO spikes.
> >
> > But....
> >
> > Few hours ago i manually started vacuum verbose on pg_attribute, now its
> > finished and i have some outputs:
> >
> > INFO: "pg_attribute": found 554728466 removable, 212058 nonremovable row
> > versions in 44550921 out of 49326696 pages DETAIL: 178215 dead row
> versions
> > cannot be removed yet. There were 53479 unused item pointers. 0 pages are
> > entirely empty. CPU 1097.53s/1949.50u sec elapsed 6337.86 sec. Query
> > returned successfully with no result in 01:47:3626 hours.
> >
> > what do you think?
> >
> > select count(*) on pg_attribute returns:
> > 158340 rows
> >
> > So as i understand vacuum full will create new pg_attribute and will
> wrote
> > those amount of "valid" rows, but still it will scan 300GB old table?
> > So estimate will be even ~same compering with regular vacuum?
>
> more or less, yes.
>
> the thing is - find and fix whatever is causing this insane churn of
> tables/attributes.
>
> Best regards,
>
> depesz
>
>