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Allow an autovacuum worker to be interrupted automatically when it is found

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to be locking another process (except when it's working to prevent Xid
wraparound problems).
This commit is contained in:
Alvaro Herrera
2007-10-26 20:45:10 +00:00
parent ffda32e9fd
commit acac68b2bc
5 changed files with 114 additions and 7 deletions
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50
src/backend/storage/lmgr/proc.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/storage/lmgr/proc.c,v 1.195 2007/10/24 20:55:36 alvherre Exp $
* $PostgreSQL: pgsql/src/backend/storage/lmgr/proc.c,v 1.196 2007/10/26 20:45:10 alvherre Exp $
*
*-------------------------------------------------------------------------
*/
@ -734,6 +734,7 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
PROC_QUEUE *waitQueue = &(lock->waitProcs);
LOCKMASK myHeldLocks = MyProc->heldLocks;
bool early_deadlock = false;
bool allow_autovacuum_cancel = true;
int myWaitStatus;
PGPROC *proc;
int i;
@ -893,6 +894,48 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
*/
myWaitStatus = MyProc->waitStatus;
/*
* If we are not deadlocked, but are waiting on an autovacuum-induced
* task, send a signal to interrupt it.
*/
if (deadlock_state == DS_BLOCKED_BY_AUTOVACUUM && allow_autovacuum_cancel)
{
PGPROC *autovac = GetBlockingAutoVacuumPgproc();
LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
/*
* Only do it if the worker is not working to protect against Xid
* wraparound.
*/
if ((autovac != NULL) &&
(autovac->vacuumFlags & PROC_IS_AUTOVACUUM) &&
!(autovac->vacuumFlags & PROC_VACUUM_FOR_WRAPAROUND))
{
int pid = autovac->pid;
elog(DEBUG2, "sending cancel to blocking autovacuum pid = %d",
pid);
/* don't hold the lock across the kill() syscall */
LWLockRelease(ProcArrayLock);
/* send the autovacuum worker Back to Old Kent Road */
if (kill(pid, SIGINT) < 0)
{
/* Just a warning to allow multiple callers */
ereport(WARNING,
(errmsg("could not send signal to process %d: %m",
pid)));
}
}
else
LWLockRelease(ProcArrayLock);
/* prevent signal from being resent more than once */
allow_autovacuum_cancel = false;
}
/*
* If awoken after the deadlock check interrupt has run, and
* log_lock_waits is on, then report about the wait.
@ -1189,13 +1232,16 @@ CheckDeadLock(void)
* RemoveFromWaitQueue took care of waking up any such processes.
*/
}
else if (log_lock_waits)
else if (log_lock_waits || deadlock_state == DS_BLOCKED_BY_AUTOVACUUM)
{
/*
* Unlock my semaphore so that the interrupted ProcSleep() call can
* print the log message (we daren't do it here because we are inside
* a signal handler). It will then sleep again until someone
* releases the lock.
*
* If blocked by autovacuum, this wakeup will enable ProcSleep to send
* the cancelling signal to the autovacuum worker.
*/
PGSemaphoreUnlock(&MyProc->sem);
}