Horton

Re: Should vacuum process config file reload more often

Masahiko Sawada <sawada.mshk@gmail.com>

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From: Masahiko Sawada <sawada.mshk@gmail.com>
To: Daniel Gustafsson <daniel@yesql.se>
Cc: Melanie Plageman <melanieplageman@gmail.com>, Robert Haas <robertmhaas@gmail.com>, Andres Freund <andres@anarazel.de>, Tom Lane <tgl@sss.pgh.pa.us>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Amit Kapila <amit.kapila16@gmail.com>
Date: 2023-04-17T02:04:22Z
Lists: pgsql-hackers

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On Wed, Apr 12, 2023 at 12:05 AM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>
> On Fri, Apr 7, 2023 at 10:23 PM Daniel Gustafsson <daniel@yesql.se> wrote:
> >
> > > On 7 Apr 2023, at 15:07, Melanie Plageman <melanieplageman@gmail.com> wrote:
> > > On Fri, Apr 7, 2023 at 2:53 AM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> > >
> > > Definitely seems worth fixing as it kind of defeats the purpose of the
> > > original commit. I wish I had noticed before!
> > >
> > > Your fix has:
> > >            !(avopts && (avopts->vacuum_cost_limit >= 0 ||
> > >                        avopts->vacuum_cost_delay >= 0));
> > >
> > > And though delay is required to be >= 0
> > >                        avopts->vacuum_cost_delay >= 0
> > >
> > > Limit does not. It can just be > 0.
> > >
> > > postgres=# create table foo (a int) with (autovacuum_vacuum_cost_limit = 0);
> > > ERROR:  value 0 out of bounds for option "autovacuum_vacuum_cost_limit"
> > > DETAIL:  Valid values are between "1" and "10000".
> > >
> > > Though >= is also fine, the rest of the code in all versions always
> > > checks if limit > 0 and delay >= 0 since 0 is a valid value for delay
> > > and not for limit. Probably best we keep it consistent (though the whole
> > > thing is quite confusing).
> >
> > +1
>
> +1. I misunderstood the initial value of autovacuum_vacuum_cost_limit reloption.

I've attached an updated patch for fixing at_dobalance condition.

Regards,

-- 
Masahiko Sawada
Amazon Web Services: https://aws.amazon.com

Commits

  1. Fix assertion failure in heap_vacuum_rel

  2. Fix vacuum_cost_delay check for balance calculation.

  3. Fix autovacuum cost debug logging

  4. Refresh cost-based delay params more frequently in autovacuum

  5. Separate vacuum cost variables from GUCs

  6. Make vacuum failsafe_active globally visible

  7. Don't balance vacuum cost delay when per-table settings are in effect