Horton

Re: per backend WAL statistics

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Michael Paquier <michael@paquier.xyz>
Cc: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>, Andres Freund <andres@anarazel.de>, Xuneng Zhou <xunengzhou@gmail.com>, pgsql-hackers@lists.postgresql.org
Date: 2025-03-12T03:14:24Z
Lists: pgsql-hackers 
Michael Paquier <michael@paquier.xyz> writes:
> And I guess that we're OK here, so applied.  That should be the last
> one.

Quite a few buildfarm members are not happy about the initialization
that 9a8dd2c5a added to PendingBackendStats.  For instance [1]:

gcc -std=gnu99 -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Werror=vla -Wendif-labels -Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -fexcess-precision=standard -g -O2 -I. -I. -I../../../../src/include  -D_GNU_SOURCE -I/usr/include/libxml2   -c -o pgstat_backend.o pgstat_backend.c
pgstat_backend.c:39:1: warning: missing braces around initializer [-Wmissing-braces]
 static PgStat_BackendPending PendingBackendStats = {0};
 ^
pgstat_backend.c:39:1: warning: (near initialization for \342\200\230PendingBackendStats.pending_io\342\200\231) [-Wmissing-braces]

I guess that more than one level of braces is needed for this to
be fully correct?  Similar from ayu, batfish, boa, buri, demoiselle,
dhole, rhinoceros, shelduck, siskin.

			regards, tom lane

[1] https://buildfarm.postgresql.org/cgi-bin/show_stage_log.pl?nm=arowana&dt=2025-03-11%2004%3A59%3A16&stg=build

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