Horton

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

Kyotaro Horiguchi <horikyota.ntt@gmail.com>

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From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
To: melanieplageman@gmail.com
Cc: andres@anarazel.de, tgl@sss.pgh.pa.us, vignesh21@gmail.com, pryzby@telsasoft.com, lukas@fittl.com, alvherre@alvh.no-ip.org, magnus@hagander.net, pgsql-hackers@postgresql.org, thomas.munro@gmail.com, m.sakrejda@gmail.com
Date: 2023-03-07T02:55:10Z
Lists: pgsql-hackers 
At Mon, 6 Mar 2023 15:21:14 -0500, Melanie Plageman <melanieplageman@gmail.com> wrote in 
> On Mon, Mar 6, 2023 at 2:34 PM Andres Freund <andres@anarazel.de> wrote:
> > That, but also because it's simply more reliable. autovacuum=off doesn't
> > protect against a anti-wraparound vacuum or such. Or a concurrent test somehow
> > triggering a read. Or ...
>
> Good point. Attached is what you suggested. I committed the transaction
> before the drop table so that the statistics would be visible when we
> queried pg_stat_io.

While I don't believe anti-wraparound vacuum can occur during testing,
Melanie's solution (moving the commit by a few lines) seems working
(by a manual testing).

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center

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.