Function ExecShutdownNode

src/backend/executor/execProcnode.c:1349–1401

* ExecShutdownNode * * Give execution nodes a chance to stop asynchronous resource consumption * and release any resources still held. */

 * and release any resources still held.
 */
bool
ExecShutdownNode(PlanState *node)
{
	if (node == NULL)
		return false;

	check_stack_depth();

	/*
	 * Treat the node as running while we shut it down, but only if it's run
	 * at least once already.  We don't expect much CPU consumption during
	 * node shutdown, but in the case of Gather or Gather Merge, we may shut
	 * down workers at this stage.  If so, their buffer usage will get
	 * propagated into pgBufferUsage at this point, and we want to make sure
	 * that it gets associated with the Gather node.  We skip this if the node
	 * has never been executed, so as to avoid incorrectly making it appear
	 * that it has.
	 */
	if (node->instrument && node->instrument->running)
		InstrStartNode(node->instrument);

	planstate_tree_walker(node, ExecShutdownNode, NULL);

	switch (nodeTag(node))
	{
		case T_GatherState:
			ExecShutdownGather((GatherState *) node);
			break;
		case T_ForeignScanState:
			ExecShutdownForeignScan((ForeignScanState *) node);
			break;
		case T_CustomScanState:
			ExecShutdownCustomScan((CustomScanState *) node);
			break;
		case T_GatherMergeState:
			ExecShutdownGatherMerge((GatherMergeState *) node);
			break;
		case T_HashState:
			ExecShutdownHash((HashState *) node);
			break;
		case T_HashJoinState:
			ExecShutdownHashJoin((HashJoinState *) node);
			break;
		default:
			break;
	}

	/* Stop the node if we started it above, reporting 0 tuples. */
	if (node->instrument && node->instrument->running)
		InstrStopNode(node->instrument, 0);

	return false;
}

/*
 * ExecSetTupleBound