Horton

Re: another autovacuum scheduling thread

wenhui qiu <qiuwenhuifx@gmail.com>

View thread
From: wenhui qiu <qiuwenhuifx@gmail.com>
To: Sami Imseih <samimseih@gmail.com>
Cc: Nathan Bossart <nathandbossart@gmail.com>, David Rowley <dgrowleyml@gmail.com>, Robert Haas <robertmhaas@gmail.com>, Jeremy Schneider <schneider@ardentperf.com>, pgsql-hackers@postgresql.org
Date: 2025-10-29T03:10:55Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Add rudimentary table prioritization to autovacuum.

  2. Trigger more frequent autovacuums with relallfrozen

  3. Harden nbtree page deletion.

  4. Check for interrupts inside the nbtree page deletion code.

HI Nathan Bossart

> + if (vactuples > vacthresh)
> + {
> + *dovacuum = true;
> + *score = Max(*score, (double) vactuples / Max(vacthresh, 1));
> + }
> +
> + if (vac_ins_base_thresh >= 0 && instuples > vacinsthresh)
> + {
> + *dovacuum = true;
> + *score = *score = Max(*score, (double) instuples / Max(vacinsthresh,
1));
> + }
 I think it ( *score = *score = Max(*score, (double) instuples /
Max(vacinsthresh, 1));) I believe this must be a slip of the hand on your
part, having copied an extra one.
I also suggest add debug log for score
    ereport(DEBUG2,
            (errmsg("autovacuum candidate: %s (score=%.3f)",
                    get_rel_name(table->oid), table->score)));

> + effective_xid_failsafe_age = Max(vacuum_failsafe_age,
> + autovacuum_freeze_max_age * 1.05);
Typically, DBAs avoid setting autovacuum_freeze_max_age too close to
vacuum_failsafe_age. Therefore, your logic most likely uses the
vacuum_failsafe_age value.
Would taking the average of the two be a better approach?
#
root@localhost:/data/pgsql/pg18data# grep vacuum_failsafe_age
postgresql.conf
#vacuum_failsafe_age = 1600000000
root@localhost:/data/pgsql/pg18data# grep autovacuum_freeze_max_age
postgresql.conf
#autovacuum_freeze_max_age = 200000000 # maximum XID age before forced
vacuum



Thanks

On Wed, Oct 29, 2025 at 6:45 AM Sami Imseih <samimseih@gmail.com> wrote:

> > Done.
>
> My compiler is complaining about v6
>
> "../src/backend/postmaster/autovacuum.c:3293:32: warning: operation on
> ‘*score’ may be undefined [-Wsequence-point]
>  3293 |                         *score = *score = Max(*score, (double)
> instuples / Max(vacinsthresh, 1));
> [2/2] Linking target src/backend/postgres"
>
> shouldn't just be like below?
>
> *score =Max(*score, (double) instuples / Max(vacinsthresh, 1));
>
>
> --
> Sami
>
>
>