Function ExecSquelchNode

src/backend/executor/execAmi.c:762–934

* ExecSquelchNode * * When a node decides that it will not consume any more input tuples from a * subtree that has not yet returned end-of-data, it must call * ExecSquelchNode() on the subtree. * * This is necessary, to avoid deadlock with Motion nodes. There might be a * receiving Motion node in the subtree, and it needs to let the sender side * of the Motion know that we will not be read

 * when force is true.
 */
void
ExecSquelchNode(PlanState *node, bool force)
{
	ListCell   *lc;

	if (!node)
		return;

	switch (nodeTag(node))
	{
		case T_MotionState:
			ExecSquelchMotion((MotionState *) node, force);
			break;

		case T_ModifyTableState:
			ExecSquelchModifyTable((ModifyTableState *) node, force);
			return;

			/*
			 * Node types that need custom code to recurse.
			 */
		case T_AppendState:
			ExecSquelchAppend((AppendState *) node, force);
			break;

		case T_MergeAppendState:
			ExecSquelchMergeAppend((MergeAppendState *) node, force);
			break;

		case T_SequenceState:
			ExecSquelchSequence((SequenceState *) node, force);
			break;

		case T_SubqueryScanState:
			ExecSquelchSubqueryScan((SubqueryScanState *) node, force);
			break;

			/*
			 * Node types that need no special handling, just recurse to
			 * children.
			 */
		case T_AssertOpState:
		case T_BitmapAndState:
		case T_BitmapOrState:
		case T_RuntimeFilterState:
		case T_DynamicBitmapHeapScanState:
		case T_LimitState:
		case T_LockRowsState:
		case T_NestLoopState:
		case T_MergeJoinState:
		case T_SetOpState:
		case T_UniqueState:
		case T_HashState:
		case T_PartitionSelectorState:
		case T_WorkTableScanState:
		case T_ResultState:
		case T_ProjectSetState:
			node->squelched = true;