Function ExecReScanRecursiveUnion

src/backend/executor/nodeRecursiveunion.c:319–357

---------------------------------------------------------------- * ExecReScanRecursiveUnion * * Rescans the relation. * ---------------------------------------------------------------- */

 * ----------------------------------------------------------------
 */
void
ExecReScanRecursiveUnion(RecursiveUnionState *node)
{
	PlanState  *outerPlan = outerPlanState(node);
	PlanState  *innerPlan = innerPlanState(node);
	RecursiveUnion *plan = (RecursiveUnion *) node->ps.plan;

	/*
	 * Set recursive term's chgParam to tell it that we'll modify the working
	 * table and therefore it has to rescan.
	 */
	innerPlan->chgParam = bms_add_member(innerPlan->chgParam, plan->wtParam);

	/*
	 * if chgParam of subnode is not null then plan will be re-scanned by
	 * first ExecProcNode.  Because of above, we only have to do this to the
	 * non-recursive term.
	 */
	if (outerPlan->chgParam == NULL)
		ExecReScan(outerPlan);

	/* Release any hashtable storage */
	if (node->tableContext)
		MemoryContextResetAndDeleteChildren(node->tableContext);

	/* And rebuild empty hashtable if needed */
	/*
	 * RECURSIVE_CTE_FIXME: It suppose plan->numCols should be 0 if we don't
	 * support recursive union. QP should fix this later.
	 */
	if (plan->numCols > 0)
		ResetTupleHashTable(node->hashtable);

	/* reset processing state */
	node->recursing = false;
	node->intermediate_empty = true;
	tuplestore_clear(node->working_table);
	tuplestore_clear(node->intermediate_table);
}

void
ExecSquelchRecursiveUnion(RecursiveUnionState *node, bool force)