Horton

Re: pg_stat_bgwriter.buffers_backend is pretty meaningless (and more?)

Melanie Plageman <melanieplageman@gmail.com>

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From: Melanie Plageman <melanieplageman@gmail.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Andres Freund <andres@anarazel.de>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, Magnus Hagander <magnus@hagander.net>, Pg Hackers <pgsql-hackers@postgresql.org>, Lukas Fittl <lukas@fittl.com>, Thomas Munro <thomas.munro@gmail.com>
Date: 2021-09-29T20:46:07Z
Lists: pgsql-hackers

Attachments

On Mon, Sep 27, 2021 at 2:58 PM Melanie Plageman
<melanieplageman@gmail.com> wrote:
>
> On Fri, Sep 24, 2021 at 5:58 PM Melanie Plageman
> <melanieplageman@gmail.com> wrote:
> >
> > On Thu, Sep 23, 2021 at 5:05 PM Melanie Plageman
> > <melanieplageman@gmail.com> wrote:
> > The only remaining TODOs are described in the commit message.
> > most critical one is that the reset message doesn't work.
>
> v10 is attached with updated comments and some limited code refactoring

v11 has fixed the oversize message issue by sending a reset message for
each backend type. Now, we will call GetCurrentTimestamp
BACKEND_NUM_TYPES times, so maybe I should add some kind of flag to the
reset message that indicates the first message so that all the "do once"
things can be done at that point.

I've also fixed a few style/cosmetic issues and updated the commit
message with a link to the thread [1] where I proposed smgrwrite() and
smgrextend() wrappers (which is where I propose to call
pgstat_incremement_buffer_access_type() for unbuffered writes and
extends).

- Melanie

[1] https://www.postgresql.org/message-id/CAAKRu_aw72w70X1P%3Dba20K8iGUvSkyz7Yk03wPPh3f9WgmcJ3g%40mail.gmail.com

Commits

  1. Stabilize pg_stat_io writes test

  2. Fix flakey pg_stat_io test

  3. Suppress more compiler warnings in new pgstats code.

  4. Suppress compiler warnings in new pgstats code.

  5. Add tests for pg_stat_io

  6. Create regress_tblspc in test_setup

  7. Add pg_stat_io view, providing more detailed IO statistics

  8. pgstat: Track more detailed relation IO statistics

  9. pgstat: Infrastructure for more detailed IO statistics

  10. doc: Fix some issues in logical replication section

  11. Manual cleanup and pgindent of pgstat and bufmgr related code

  12. Have the planner consider Incremental Sort for DISTINCT

  13. Use actual backend IDs in pg_stat_get_backend_idset() and friends.

  14. Remove redundant call to pgstat_report_wal()

  15. Add BackendType for standalone backends

  16. Initialize backend status reporting during bootstrap.