Re: per backend WAL statistics

Bertrand Drouvot <bertranddrouvot.pg@gmail.com>

From: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
To: Michael Paquier <michael@paquier.xyz>
Cc: Andres Freund <andres@anarazel.de>, pgsql-hackers@lists.postgresql.org
Date: 2025-02-05T14:28:08Z
Lists: pgsql-hackers
Hi,

On Wed, Feb 05, 2025 at 07:31:13PM +0900, Michael Paquier wrote:
> On Wed, Feb 05, 2025 at 10:22:55AM +0000, Bertrand Drouvot wrote:
> > So, wal_buffers_full has been introduced after the WalUsage structure was
> > there but I don't see any reason in the emails as to why it's not in the WalUsage
> > structure (I might have missed it though).
> > 
> > I think that this proposal makes sense but would need a dedicated thread,
> > thoughts?
> 
> Using a separate thread for a change like that makes sense to me.  I
> have to admit that the simplifications in terms of designs for what
> we're discussing here makes such a change more valuable.  Adding this
> information to WalUsage is one thing.  Showing it in EXPLAIN is a
> second thing.  Doing the former simplifies the patch you are proposing
> here.  We don't necessarily have to do the latter, but I don't see a
> reason to not do it, either.

Agree, I'll start a dedicated thread for that.

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com



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