Function ResLockUpdateLimit

src/backend/utils/resscheduler/resqueue.c:1020–1092

* ResLockUpdateLimit -- update the resource counter for this lock with the * increment for the process. * * Notes: * If increment is true, then the resource counter associated with the lock * is to be incremented, if false then decremented. * * Warnings: * The resource queue lightweight lock (ResQueueLock) must be held while * this function is called. */

 *	this function is called.
 */
void
ResLockUpdateLimit(LOCK *lock, PROCLOCK *proclock, ResPortalIncrement *incrementSet, bool increment, bool inError)
{
	ResQueue	queue;
	ResLimit	limits;
	Cost		increment_amt;
	int			i;

	Assert(LWLockHeldByMeInMode(ResQueueLock, LW_EXCLUSIVE));

	/* Get the queue for this lock. */
	queue = GetResQueueFromLock(lock);
	limits = queue->limits;

	/*
	 * If inError is true, dump the rq info and stack to track
	 * where ResLockUpdateLimit() was called.
	 */
	if (inError)
	{
		Assert(limits[0].type == RES_COUNT_LIMIT);
		elog(LOG,
			 "Resource queue id: %u, count limit: %f, portal id: %u\n",
			 queue->queueid,
			 limits[0].current_value,
			 incrementSet->portalId);
		ereport(LOG,
				(errmsg("ResLockUpdateLimit()"),
				errprintstack(true)));
	}

	for (i = 0; i < NUM_RES_LIMIT_TYPES; i++)
	{
		/*
		 * MPP-8454: NOTE that if our resource-queue has been modified since
		 * we locked our resources, on unlock it is possible that we're
		 * deducting an increment that we never added -- the lowest value we
		 * should allow is 0.0.
		 *
		 */
		switch (limits[i].type)
		{
			case RES_COUNT_LIMIT:
			case RES_COST_LIMIT:
			case RES_MEMORY_LIMIT:
				{
					Cost		new_value;

					Assert((limits[i].threshold_is_max));
					/* setup whether to increment or decrement the # active. */
					if (increment)
					{
						increment_amt = incrementSet->increments[i];
					}
					else
					{
						increment_amt = -1 * incrementSet->increments[i];
					}