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Merge pull request #1777 from citusdata/skip_page_locks 

Skip page-level locks for distributed deadlock detection
pull/1774/head^2
Önder Kalacı 2017-11-09 13:01:21 +03:00 committed by GitHub
parent a85a973c3e 94921a2be1
commit 14ff31704c
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 21 additions and 20 deletions
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41
src/backend/distributed/transaction/lock_graph.c
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@ -49,7 +49,7 @@ static bool ParseBoolField(PGresult *result, int rowIndex, int colIndex);
static TimestampTz ParseTimestampTzField(PGresult *result, int rowIndex, int colIndex);
static void ReturnWaitGraph(WaitGraph *waitGraph, FunctionCallInfo fcinfo);
static WaitGraph * BuildLocalWaitGraph(void);
static bool IsProcessWaitingForRelationExtension(PGPROC *proc);
static bool IsProcessWaitingForSafeOperations(PGPROC *proc);
static void LockLockData(void);
static void UnlockLockData(void);
static void AddEdgesForLockWaits(WaitGraph *waitGraph, PGPROC *waitingProc,
@ -449,7 +449,7 @@ BuildLocalWaitGraph(void)
}
/* skip if the process is blocked for relation extension */
if (IsProcessWaitingForRelationExtension(currentProc))
if (IsProcessWaitingForSafeOperations(currentProc))
{
continue;
}
@ -468,7 +468,7 @@ BuildLocalWaitGraph(void)
}
/* skip if the process is blocked for relation extension */
if (IsProcessWaitingForRelationExtension(waitingProc))
if (IsProcessWaitingForSafeOperations(waitingProc))
{
continue;
}
@ -493,19 +493,19 @@ BuildLocalWaitGraph(void)
/*
* IsProcessWaitingForRelationExtension returns true if the given PROC
* waiting on relation extension lock.
* IsProcessWaitingForSafeOperations returns true if the given PROC
* waiting on relation extension lock or page locks.
*
* In general for the purpose of distributed deadlock detection, we should
* skip if the process blocked on the relation extension. Those locks are
* held for a short duration while the relation is actually extended on
* the disk and released as soon as the extension is done, even before the
* execution of the command that triggered the extension finishes. Thus,
* recording such waits on our lock graphs could yield detecting wrong
* distributed deadlocks.
* skip if the process blocked on the locks that may not be part of deadlocks.
* Those locks are held for a short duration while the relation or the index
* is actually extended on the disk and released as soon as the extension is
* done, even before the execution of the command that triggered the extension
* finishes. Thus, recording such waits on our lock graphs could yield detecting
* wrong distributed deadlocks.
*/
static bool
IsProcessWaitingForRelationExtension(PGPROC *proc)
IsProcessWaitingForSafeOperations(PGPROC *proc)
{
PROCLOCK *waitProcLock = NULL;
LOCK *waitLock = NULL;
@ -518,7 +518,8 @@ IsProcessWaitingForRelationExtension(PGPROC *proc)
waitProcLock = proc->waitProcLock;
waitLock = waitProcLock->tag.myLock;
return waitLock->tag.locktag_type == LOCKTAG_RELATION_EXTEND;
return waitLock->tag.locktag_type == LOCKTAG_RELATION_EXTEND ||
waitLock->tag.locktag_type == LOCKTAG_PAGE;
}
@ -595,12 +596,12 @@ AddEdgesForLockWaits(WaitGraph *waitGraph, PGPROC *waitingProc, PROCStack *remai
/*
* Skip processes from the same lock group, processes that don't conflict,
* and processes that are waiting on a relation extension lock, which
* will be released shortly.
* and processes that are waiting on a relation extension lock or page locks,
* which will be released shortly.
*/
if (!IsSameLockGroup(waitingProc, currentProc) &&
IsConflictingLockMask(procLock->holdMask, conflictMask) &&
!IsProcessWaitingForRelationExtension(currentProc))
!IsProcessWaitingForSafeOperations(currentProc))
{
AddWaitEdge(waitGraph, waitingProc, currentProc, remaining);
}
@ -640,12 +641,12 @@ AddEdgesForWaitQueue(WaitGraph *waitGraph, PGPROC *waitingProc, PROCStack *remai
/*
* Skip processes from the same lock group, processes that don't conflict,
* and processes that are waiting on a relation extension lock, which
* will be released shortly.
* and processes that are waiting on a relation extension lock or page locks,
* which will be released shortly.
*/
if (!IsSameLockGroup(waitingProc, currentProc) &&
IsConflictingLockMask(awaitMask, conflictMask) &&
!IsProcessWaitingForRelationExtension(currentProc))
!IsProcessWaitingForSafeOperations(currentProc))
{
AddWaitEdge(waitGraph, waitingProc, currentProc, remaining);
}
@ -676,7 +677,7 @@ AddWaitEdge(WaitGraph *waitGraph, PGPROC *waitingProc, PGPROC *blockingProc,
curEdge->isBlockingXactWaiting =
IsProcessWaitingForLock(blockingProc) &&
!IsProcessWaitingForRelationExtension(blockingProc);
!IsProcessWaitingForSafeOperations(blockingProc);
if (curEdge->isBlockingXactWaiting)
{
AddProcToVisit(remaining, blockingProc);