Function ResRemoveFromWaitQueue

src/backend/utils/resscheduler/resqueue.c:1494–1554

* ResRemoveFromWaitQueue -- Remove a process from the wait queue, cleaning up * any locks. */

 *	any locks.
 */
void
ResRemoveFromWaitQueue(PGPROC *proc, uint32 hashcode)
{
	LOCK	   *waitLock = proc->waitLock;
	PROCLOCK   *proclock = proc->waitProcLock;
	LOCKMODE	lockmode = proc->waitLockMode;
#ifdef USE_ASSERT_CHECKING
	LOCKMETHODID lockmethodid = LOCK_LOCKMETHOD(*waitLock);
#endif   /* USE_ASSERT_CHECKING */
	ResPortalTag portalTag;

	/* Make sure lockmethod is for a resource lock. */
	Assert(lockmethodid == RESOURCE_LOCKMETHOD);

	/* Make sure proc is waiting */
	Assert(proc->links.next != NULL);
	Assert(waitLock);
	Assert(waitLock->waitProcs.size > 0);

	/* Remove proc from lock's wait queue */
	SHMQueueDelete(&(proc->links));
	waitLock->waitProcs.size--;

	/* Undo increments of request counts by waiting process */
	Assert(waitLock->nRequested > 0);
	Assert(waitLock->nRequested > proc->waitLock->nGranted);

	waitLock->nRequested--;
	Assert(waitLock->requested[lockmode] > 0);
	waitLock->requested[lockmode]--;

	/* don't forget to clear waitMask bit if appropriate */
	if (waitLock->granted[lockmode] == waitLock->requested[lockmode])
		waitLock->waitMask &= LOCKBIT_OFF(lockmode);

	/* Clean up the proc's own state */
	proc->waitLock = NULL;
	proc->waitProcLock = NULL;
	proc->waitStatus = STATUS_ERROR;

	/*
	 * Remove the waited on portal increment.
	 */
	MemSet(&portalTag, 0, sizeof(ResPortalTag));
	portalTag.pid = MyProc->pid;
	portalTag.portalId = MyProc->waitPortalId;

	LWLockAcquire(ResQueueLock, LW_EXCLUSIVE);
	ResIncrementRemove(&portalTag);

	/*
	 * Delete the proclock immediately if it represents no already-held locks.
	 * (This must happen now because if the owner of the lock decides to
	 * release it, and the requested/granted counts then go to zero,
	 * LockRelease expects there to be no remaining proclocks.) Then see if
	 * any other waiters for the lock can be woken up now.
	 */
	ResCleanUpLock(waitLock, proclock, hashcode, true);