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Skip speculative locks for distributed deadlock detection 

These locks are held for a very short duration time and cannot
contribute to a deadlock. Speculative locks are used by Postgres
for internal notification mechanism among transactions.
pull/2077/head
Onder Kalaci 2017-11-15 10:47:01 +02:00 committed by velioglu
parent e1d51432ee
commit fbfe5385cb
1 changed files with 5 additions and 6 deletions
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11
src/backend/distributed/transaction/lock_graph.c
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@ -494,7 +494,7 @@ BuildLocalWaitGraph(void)
/*
* IsProcessWaitingForSafeOperations returns true if the given PROC
* waiting on relation extension lock or page locks.
* waiting on relation extension locks, page locks or speculative locks.
*
* In general for the purpose of distributed deadlock detection, we should
* skip if the process blocked on the locks that may not be part of deadlocks.
@ -519,7 +519,8 @@ IsProcessWaitingForSafeOperations(PGPROC *proc)
waitLock = waitProcLock->tag.myLock;
return waitLock->tag.locktag_type == LOCKTAG_RELATION_EXTEND ||
waitLock->tag.locktag_type == LOCKTAG_PAGE;
waitLock->tag.locktag_type == LOCKTAG_PAGE ||
waitLock->tag.locktag_type == LOCKTAG_SPECULATIVE_TOKEN;
}
@ -596,8 +597,7 @@ 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 or page locks,
* which will be released shortly.
* and processes that are waiting on safe operations.
*/
if (!IsSameLockGroup(waitingProc, currentProc) &&
IsConflictingLockMask(procLock->holdMask, conflictMask) &&
@ -641,8 +641,7 @@ 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 or page locks,
* which will be released shortly.
* and processes that are waiting on safe operations.
*/
if (!IsSameLockGroup(waitingProc, currentProc) &&
IsConflictingLockMask(awaitMask, conflictMask) &&