Horton

Re: per backend WAL statistics

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, pgsql-hackers@lists.postgresql.org, Nazir Bilal Yavuz <byavuz81@gmail.com>
Date: 2025-02-28T12:22:16Z
Lists: pgsql-hackers 
On Fri, Feb 28, 2025 at 09:26:08AM +0000, Bertrand Drouvot wrote:
> Also attaching the patch I mentioned up-thread to address some of Rahila's
> comments ([1]): It adds a AuxiliaryPidGetProc() call in pgstat_fetch_stat_backend_by_pid()
> and pg_stat_reset_backend_stats(). I think that fully makes sense since a051e71e28a
> modified pgstat_tracks_backend_bktype() for B_WAL_RECEIVER, B_WAL_SUMMARIZER
> and B_WAL_WRITER.

Oops, yes, you are right on this one.  This change should have
happened earlier.  The flow you are using in 0002 is similar to
pg_log_backend_memory_contexts(), which looks OK at quick glance.
--
Michael

Commits

  1. Fix use-after-free in pgstat_fetch_stat_backend_by_pid()

  2. Remove initialization from PendingBackendStats

  3. Add WAL data to backend statistics

  4. Improve check for detection of pending data in backend statistics

  5. Fix some gaps in pg_stat_io with WAL receiver and WAL summarizer

  6. Handle auxiliary processes in SQL functions of backend statistics

  7. Invent pgstat_fetch_stat_backend_by_pid()

  8. Refactor code of pg_stat_get_wal() building result tuple

  9. Adding new PgStat_WalCounters structure in pgstat.h

  10. Remove pgstat_flush_wal()

  11. Refactor some code related to backend statistics

  12. Add backend-level statistics to pgstats