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| author | Michael Paquier <michael@paquier.xyz> | 2025-02-26 09:49:59 +0900 |
|---|---|---|
| committer | Michael Paquier <michael@paquier.xyz> | 2025-02-26 09:49:59 +0900 |
| commit | 6c349d83b607cfe20a685a5f66a4fa0e24dbe458 (patch) | |
| tree | f40e52d4a8571f996976ffe0876b989921e9a998 /src/backend/access/transam/xlogreader.c | |
| parent | a5cbdeb98af9a8d4f683fbffa69cd74be1f4a084 (diff) | |
| download | postgresql-6c349d83b607cfe20a685a5f66a4fa0e24dbe458.tar.gz postgresql-6c349d83b607cfe20a685a5f66a4fa0e24dbe458.zip | |
Re-add GUC track_wal_io_timing
This commit is a rework of 2421e9a51d20, about which Andres Freund has
raised some concerns as it is valuable to have both track_io_timing and
track_wal_io_timing in some cases, as the WAL write and fsync paths can
be a major bottleneck for some workloads. Hence, it can be relevant to
not calculate the WAL timings in environments where pg_test_timing
performs poorly while capturing some IO data under track_io_timing for
the non-WAL IO paths. The opposite can be also true: it should be
possible to disable the non-WAL timings and enable the WAL timings (the
previous GUC setups allowed this possibility).
track_wal_io_timing is added back in this commit, controlling if WAL
timings should be calculated in pg_stat_io for the read, fsync and write
paths, as done previously with pg_stat_wal. pg_stat_wal previously
tracked only the sync and write parts (now removed), read stats is new
data tracked in pg_stat_io, all three are aggregated if
track_wal_io_timing is enabled. The read part matters during recovery
or if a XLogReader is used.
Extra note: more control over if the types of timings calculated in
pg_stat_io could be done with a GUC that lists pairs of (IOObject,IOOp).
Reported-by: Andres Freund <andres@anarazel.de>
Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Co-authored-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/3opf2wh2oljco6ldyqf7ukabw3jijnnhno6fjb4mlu6civ5h24@fcwmhsgmlmzu
Diffstat (limited to 'src/backend/access/transam/xlogreader.c')
| -rw-r--r-- | src/backend/access/transam/xlogreader.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 995e4f7c26f..5483d4f0dd2 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -1557,7 +1557,7 @@ WALRead(XLogReaderState *state, #ifndef FRONTEND /* Measure I/O timing when reading segment */ - io_start = pgstat_prepare_io_time(); + io_start = pgstat_prepare_io_time(track_wal_io_timing); pgstat_report_wait_start(WAIT_EVENT_WAL_READ); #endif |