Function ResLockCheckLimit

src/backend/utils/resscheduler/resqueue.c:874–1005

* ResLockCheckLimit -- test whether the given process acquiring the this lock * will cause a resource to exceed its limits. * * Notes: * Returns LIMIT_CHECK_FOUND if limit will be exhausted, LIMIT_CHECK_OK if not. * * If increment is true, then the resource counter associated with the lock * is to be incremented, if false then decremented. * * Named similarly to the LockCheckconflicts() f

 * them from freeing resources!
 */
int
ResLockCheckLimit(LOCK *lock, PROCLOCK *proclock, ResPortalIncrement *incrementSet, bool increment)
{
	ResQueue	queue;
	ResLimit	limits;
	bool		over_limit = false;
	bool		will_overcommit = false;
	int			status = LIMIT_CHECK_OK;
	Cost		increment_amt;
	int			i;

	Assert(LWLockHeldByMeInMode(ResQueueLock, LW_EXCLUSIVE));

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

	for (i = 0; i < NUM_RES_LIMIT_TYPES; i++)
	{
		/*
		 * Skip the default threshold, as it means 'no limit'.
		 */
		if (limits[i].threshold_value == INVALID_RES_LIMIT_THRESHOLD)
			continue;

		switch (limits[i].type)
		{
			case RES_COUNT_LIMIT:
				{
					Assert((limits[i].threshold_is_max));

					/* Setup whether to increment or decrement the # active. */
					if (increment)
					{
						increment_amt = incrementSet->increments[i];

						if (limits[i].current_value + increment_amt > limits[i].threshold_value)
							over_limit = true;
					}
					else
					{
						increment_amt = -1 * incrementSet->increments[i];
					}

#ifdef RESLOCK_DEBUG
					elog(DEBUG1, "checking count limit threshold %.0f current %.0f",
						 limits[i].threshold_value, limits[i].current_value);
#endif
				}
				break;

			case RES_COST_LIMIT:
				{
					Assert((limits[i].threshold_is_max));

					/* Setup whether to increment or decrement the cost. */
					if (increment)
					{