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Extend relations multiple blocks at a time to improve scalability.

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Contention on the relation extension lock can become quite fierce when
multiple processes are inserting data into the same relation at the same
time at a high rate.  Experimentation shows the extending the relation
multiple blocks at a time improves scalability.

Dilip Kumar, reviewed by Petr Jelinek, Amit Kapila, and me.
This commit is contained in:
Robert Haas
2016-04-08 02:04:46 -04:00
parent 8643b91ecf
commit 719c84c1be
7 changed files with 271 additions and 3 deletions
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35
src/backend/storage/lmgr/lmgr.c
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@@ -340,6 +340,41 @@ LockRelationForExtension(Relation relation, LOCKMODE lockmode)
(void) LockAcquire(&tag, lockmode, false, false);
}
/*
* ConditionalLockRelationForExtension
*
* As above, but only lock if we can get the lock without blocking.
* Returns TRUE iff the lock was acquired.
*/
bool
ConditionalLockRelationForExtension(Relation relation, LOCKMODE lockmode)
{
LOCKTAG tag;
SET_LOCKTAG_RELATION_EXTEND(tag,
relation->rd_lockInfo.lockRelId.dbId,
relation->rd_lockInfo.lockRelId.relId);
return (LockAcquire(&tag, lockmode, false, true) != LOCKACQUIRE_NOT_AVAIL);
}
/*
* RelationExtensionLockWaiterCount
*
* Count the number of processes waiting for the given relation extension lock.
*/
int
RelationExtensionLockWaiterCount(Relation relation)
{
LOCKTAG tag;
SET_LOCKTAG_RELATION_EXTEND(tag,
relation->rd_lockInfo.lockRelId.dbId,
relation->rd_lockInfo.lockRelId.relId);
return LockWaiterCount(&tag);
}
/*
* UnlockRelationForExtension
*/