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| author | Heikki Linnakangas <heikki.linnakangas@iki.fi> | 2024-06-13 19:01:30 +0300 |
|---|---|---|
| committer | Heikki Linnakangas <heikki.linnakangas@iki.fi> | 2024-06-13 19:02:51 +0300 |
| commit | 7768ac1c17f0ec7883825e8768ab480caa7842ec (patch) | |
| tree | 14f1fa907c6c543021922822ec043c3fd7055ee2 /src | |
| parent | c38518fa978075d08d64a34e1b4504da13a81e02 (diff) | |
| download | postgresql-7768ac1c17f0ec7883825e8768ab480caa7842ec.tar.gz postgresql-7768ac1c17f0ec7883825e8768ab480caa7842ec.zip | |
Clamp result of MultiXactMemberFreezeThreshold
The purpose of the function is to reduce the effective
autovacuum_multixact_freeze_max_age if the multixact members SLRU is
approaching wraparound, to make multixid freezing more aggressive.
The returned value should therefore never be greater than plain
autovacuum_multixact_freeze_max_age.
Reviewed-by: Robert Haas
Discussion: https://www.postgresql.org/message-id/85fb354c-f89f-4d47-b3a2-3cbd461c90a3@iki.fi
Backpatch-through: 12, all supported versions
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/access/transam/multixact.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c index b8b1773d16a..136065125ea 100644 --- a/src/backend/access/transam/multixact.c +++ b/src/backend/access/transam/multixact.c @@ -2832,6 +2832,7 @@ MultiXactMemberFreezeThreshold(void) uint32 multixacts; uint32 victim_multixacts; double fraction; + int result; /* If we can't determine member space utilization, assume the worst. */ if (!ReadMultiXactCounts(&multixacts, &members)) @@ -2853,7 +2854,13 @@ MultiXactMemberFreezeThreshold(void) /* fraction could be > 1.0, but lowest possible freeze age is zero */ if (victim_multixacts > multixacts) return 0; - return multixacts - victim_multixacts; + result = multixacts - victim_multixacts; + + /* + * Clamp to autovacuum_multixact_freeze_max_age, so that we never make + * autovacuum less aggressive than it would otherwise be. + */ + return Min(result, autovacuum_multixact_freeze_max_age); } typedef struct mxtruncinfo |