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In-Reply-To: <a611e91e-073d-49fe-aeb1-45d1a505b78f@yandex.ru>
From: Alexander Korotkov <aekorotkov@gmail.com>
Date: Tue, 16 Jun 2026 20:30:26 +0300
Message-ID: 
 <CAPpHfdvsNSu3vxBQK4srQk5bp1PDKkMLfbv7HhzE3D_yW9ELvg@mail.gmail.com>
Subject: Re: Vacuum statistics
To: Alena Rybakina <lena.ribackina@yandex.ru>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>,
 Masahiko Sawada <sawada.mshk@gmail.com>,
	Amit Kapila <amit.kapila16@gmail.com>, Jim Nasby <jnasby@upgrade.com>,
	Bertrand Drouvot <bertranddrouvot.pg@gmail.com>,
 Kirill Reshke <reshkekirill@gmail.com>,
	Melanie Plageman <melanieplageman@gmail.com>,
 jian he <jian.universality@gmail.com>,
	Sami Imseih <samimseih@gmail.com>, vignesh C <vignesh21@gmail.com>,
	Ilia Evdokimov <ilya.evdokimov@tantorlabs.com>,
 Andrey Borodin <x4mmm@yandex-team.ru>,
	Andrei Zubkov <zubkov@moonset.ru>, Andrei Lepikhov <lepihov@gmail.com>
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Precedence: bulk

Hi, Alena!

On Tue, Jun 16, 2026 at 6:10=E2=80=AFPM Alena Rybakina <lena.ribackina@yand=
ex.ru> wrote:
> Attached is a reworked version of the patch set. The main change is that =
the
> statistics are no longer exposed through a contrib extension; they are no=
w
> built-in system views - pg_stat_vacuum_tables, pg_stat_vacuum_indexes and
> pg_stat_vacuum_database - backed by pg_stat_get_vacuum_*() functions and =
stored
> in the cumulative statistics system under a dedicated stats kind
> (PGSTAT_KIND_VACUUM_RELATION). Collection is controlled by a single
> track_vacuum_statistics GUC; the per-relation tracking list, the reset
> function and the shared-memory-size helper from the extension version are=
 gone.
>
> The series is also split into smaller, self-contained commits - one per m=
etric
> category (core heap/tuple counters, missed dead tuples/pages, visibility-=
map
> transitions, the buffer/WAL/timing sampling machinery, per-relation buffe=
rs,
> timing and the wraparound failsafe, and WAL) - with the documentation and
> tests growing inside each commit.
>
> Other changes:
>
> index statistics are accumulated across the bulkdelete and cleanup passes=
 and reported once per index, in both the serial and parallel paths;
> index_vacuum_count is no longer exposed;
> the regression coverage is now an in-core vacuum_stats test with determin=
istic checks and dedicated scenarios for the non-trivial paths (truncation,=
 freeze, cost delay, WAL full-page images, index page deletion), an isolati=
on test for recently_dead/missed_dead tuples, and a xid_wraparound TAP test=
 for the failsafe counter.

Thank you for the updated patchset.

Some notes about it.
1) PgStat_CommonCounts.interrupts_count is never incremented.
2) LVRelState.wraparound_failsafe_count can only be incremented once
in lazy_check_wraparound_failsafe().  Should we replace it with a
bool?
3) Vacuum statistics isn't counted correctly for parallel index
vacuum.  parallel_vacuum_process_one_index() doesn't call neither
extvac_stats_start_idx(), extvac_stats_end_idx(), or
extvac_accumulate_idx_repor().  This leads all index vacuum stats to
go the heap stats.  I also think you need a reliable test cases to
cover issues like this.
4) It seems that pgstat_vacuum_db_flush_cb() and
pgstat_vacuum_relation_flush_cb() are unused as
pgstat_report_vacuum_extstats() reports directly to shmem.  What was
your intention here?
5) Commit message of 0001 uses stale names
rev_all_visible_pages/rev_all_frozen_pages counters for
visible_page_marks_cleared` / `frozen_page_marks_cleared.

------
Regards,
Alexander Korotkov
Supabase