Function ExecMaterializesOutput

src/backend/executor/execAmi.c:985–1005

* ExecMaterializesOutput - does a plan type materialize its output? * * Returns true if the plan node type is one that automatically materializes * its output (typically by keeping it in a tuplestore). For such plans, * a rescan without any parameter change will have zero startup cost and * very low per-tuple cost. */

 * very low per-tuple cost.
 */
bool
ExecMaterializesOutput(NodeTag plantype)
{
	switch (plantype)
	{
		case T_Material:
		case T_FunctionScan:
		case T_TableFuncScan:
		case T_CteScan:
		case T_NamedTuplestoreScan:
		case T_WorkTableScan:
		case T_Sort:
		case T_ShareInputScan:
			return true;

		default:
			break;
	}

	return false;
}