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Skip searching for subxact locks at commit.

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At commit all standby locks are released
for the top-level transaction, so searching
for locks for each subtransaction is both
pointless and costly (N^2) in the presence
of many AccessExclusiveLocks.
This commit is contained in:
Simon Riggs 2012-11-13 16:00:19 -03:00
parent 68f7fe140b
commit d9fad1076d
1 changed files with 4 additions and 2 deletions
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6
src/backend/access/transam/xact.c
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@ -4609,9 +4609,11 @@ xact_redo_commit_internal(TransactionId xid, XLogRecPtr lsn,
/*
* Release locks, if any. We do this for both two phase and normal one
* phase transactions. In effect we are ignoring the prepare phase and
* just going straight to lock release.
* just going straight to lock release. At commit we release all locks
* via their top-level xid only, so no need to provide subxact list,
* which will save time when replaying commits.
*/
StandbyReleaseLockTree(xid, nsubxacts, sub_xids);
StandbyReleaseLockTree(xid, 0, NULL);
}
/* Make sure files supposed to be dropped are dropped */