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| author | Michael Paquier <michael@paquier.xyz> | 2022-02-10 10:27:29 +0900 |
|---|---|---|
| committer | Michael Paquier <michael@paquier.xyz> | 2022-02-10 10:27:29 +0900 |
| commit | 4567596316d186c6e61c72df013797266fcac2f7 (patch) | |
| tree | b1dba64375bc8b58dc6afd4ec041b19fb6704759 /src/backend/storage/lmgr | |
| parent | f0cd9097cfac435ec18ab2595c81f13a14736758 (diff) | |
| download | postgresql-4567596316d186c6e61c72df013797266fcac2f7.tar.gz | |
Reduce more the number of calls to GetMaxBackends()
Some of the code paths changed by aa64f23 can reduce the number of times
GetMaxBackends() is called. The performance gain is marginal, but most
of the code changed by this commit already did that. Hence, let's be
clean and apply the same rule everywhere, for consistency.
Some of the code paths, like in deadlock.c, involve only assertions.
These are left unchanged.
Reviewed-by: Nathan Bossart, Robert Haas
Discussion: https://postgr.es/m/YgMpGZhPOjNfS7er@paquier.xyz
Diffstat (limited to 'src/backend/storage/lmgr')
| -rw-r--r-- | src/backend/storage/lmgr/lock.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 1528d788d0..ee2e15c17e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -2924,6 +2924,7 @@ GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode, int *countp) LWLock *partitionLock; int count = 0; int fast_count = 0; + int max_backends = GetMaxBackends(); if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods)) elog(ERROR, "unrecognized lock method: %d", lockmethodid); @@ -2942,12 +2943,12 @@ GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode, int *countp) vxids = (VirtualTransactionId *) MemoryContextAlloc(TopMemoryContext, sizeof(VirtualTransactionId) * - (GetMaxBackends() + max_prepared_xacts + 1)); + (max_backends + max_prepared_xacts + 1)); } else vxids = (VirtualTransactionId *) palloc0(sizeof(VirtualTransactionId) * - (GetMaxBackends() + max_prepared_xacts + 1)); + (max_backends + max_prepared_xacts + 1)); /* Compute hash code and partition lock, and look up conflicting modes. */ hashcode = LockTagHashCode(locktag); @@ -3104,7 +3105,7 @@ GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode, int *countp) LWLockRelease(partitionLock); - if (count > GetMaxBackends() + max_prepared_xacts) /* should never happen */ + if (count > max_backends + max_prepared_xacts) /* should never happen */ elog(PANIC, "too many conflicting locks found"); vxids[count].backendId = InvalidBackendId; |