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In checkpoint, move the check for in-progress xacts out of critical section.

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GetVirtualXIDsDelayingChkpt calls palloc, which isn't safe in a critical
section. I thought I covered this case with the exemption for the
checkpointer, but CreateCheckPoint is also called from the startup process.
This commit is contained in:
Heikki Linnakangas
2014-04-04 17:29:50 +03:00
parent 4a170ee9e0
commit d9e7873bbb
1 changed files with 36 additions and 36 deletions
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72
src/backend/access/transam/xlog.c
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@ -8076,6 +8076,42 @@ CreateCheckPoint(int flags)
TRACE_POSTGRESQL_CHECKPOINT_START(flags); TRACE_POSTGRESQL_CHECKPOINT_START(flags);
/*
* Get the other info we need for the checkpoint record.
*/
LWLockAcquire(XidGenLock, LW_SHARED);
checkPoint.nextXid = ShmemVariableCache->nextXid;
checkPoint.oldestXid = ShmemVariableCache->oldestXid;
checkPoint.oldestXidDB = ShmemVariableCache->oldestXidDB;
LWLockRelease(XidGenLock);
/* Increase XID epoch if we've wrapped around since last checkpoint */
checkPoint.nextXidEpoch = ControlFile->checkPointCopy.nextXidEpoch;
if (checkPoint.nextXid < ControlFile->checkPointCopy.nextXid)
checkPoint.nextXidEpoch++;
LWLockAcquire(OidGenLock, LW_SHARED);
checkPoint.nextOid = ShmemVariableCache->nextOid;
if (!shutdown)
checkPoint.nextOid += ShmemVariableCache->oidCount;
LWLockRelease(OidGenLock);
MultiXactGetCheckptMulti(shutdown,
&checkPoint.nextMulti,
&checkPoint.nextMultiOffset,
&checkPoint.oldestMulti,
&checkPoint.oldestMultiDB);
/*
* Having constructed the checkpoint record, ensure all shmem disk buffers
* and commit-log buffers are flushed to disk.
*
* This I/O could fail for various reasons. If so, we will fail to
* complete the checkpoint, but there is no reason to force a system
* panic. Accordingly, exit critical section while doing it.
*/
END_CRIT_SECTION();
/* /*
* In some cases there are groups of actions that must all occur on one * In some cases there are groups of actions that must all occur on one
* side or the other of a checkpoint record. Before flushing the * side or the other of a checkpoint record. Before flushing the
@ -8116,42 +8152,6 @@ CreateCheckPoint(int flags)
} }
pfree(vxids); pfree(vxids);
/*
* Get the other info we need for the checkpoint record.
*/
LWLockAcquire(XidGenLock, LW_SHARED);
checkPoint.nextXid = ShmemVariableCache->nextXid;
checkPoint.oldestXid = ShmemVariableCache->oldestXid;
checkPoint.oldestXidDB = ShmemVariableCache->oldestXidDB;
LWLockRelease(XidGenLock);
/* Increase XID epoch if we've wrapped around since last checkpoint */
checkPoint.nextXidEpoch = ControlFile->checkPointCopy.nextXidEpoch;
if (checkPoint.nextXid < ControlFile->checkPointCopy.nextXid)
checkPoint.nextXidEpoch++;
LWLockAcquire(OidGenLock, LW_SHARED);
checkPoint.nextOid = ShmemVariableCache->nextOid;
if (!shutdown)
checkPoint.nextOid += ShmemVariableCache->oidCount;
LWLockRelease(OidGenLock);
MultiXactGetCheckptMulti(shutdown,
&checkPoint.nextMulti,
&checkPoint.nextMultiOffset,
&checkPoint.oldestMulti,
&checkPoint.oldestMultiDB);
/*
* Having constructed the checkpoint record, ensure all shmem disk buffers
* and commit-log buffers are flushed to disk.
*
* This I/O could fail for various reasons. If so, we will fail to
* complete the checkpoint, but there is no reason to force a system
* panic. Accordingly, exit critical section while doing it.
*/
END_CRIT_SECTION();
CheckPointGuts(checkPoint.redo, flags); CheckPointGuts(checkPoint.redo, flags);
/* /*