Function ExecModifyTable

src/backend/executor/nodeModifyTable.c:2630–3063

---------------------------------------------------------------- * ExecModifyTable * * Perform table modifications as required, and return RETURNING results * if needed. * ---------------------------------------------------------------- */

 * ----------------------------------------------------------------
 */
static TupleTableSlot *
ExecModifyTable(PlanState *pstate)
{
	ModifyTableState *node = castNode(ModifyTableState, pstate);
	EState	   *estate = node->ps.state;
	CmdType		operation = node->operation;
	ResultRelInfo *resultRelInfo;
	PlanState  *subplanstate;
	AttrNumber  action_attno;
	AttrNumber  segid_attno;
	TupleTableSlot *slot;
	TupleTableSlot *planSlot;
	TupleTableSlot *oldSlot;
	ItemPointer tupleid;
	ItemPointerData tuple_ctid;
	HeapTupleData oldtupdata;
	HeapTuple	oldtuple;
	PartitionTupleRouting *proute = node->mt_partition_tuple_routing;
	List	   *relinfos = NIL;
	ListCell   *lc;

	CHECK_FOR_INTERRUPTS();

	/*
	 * This should NOT get called during EvalPlanQual; we should have passed a
	 * subplan tree to EvalPlanQual, instead.  Use a runtime test not just
	 * Assert because this condition is easy to miss in testing.  (Note:
	 * although ModifyTable should not get executed within an EvalPlanQual
	 * operation, we do have to allow it to be initialized and shut down in
	 * case it is within a CTE subplan.  Hence this test must be here, not in
	 * ExecInitModifyTable.)
	 */
	if (estate->es_epq_active != NULL)
		elog(ERROR, "ModifyTable should not be called during EvalPlanQual");

	/*
	 * If we've already completed processing, don't try to do more.  We need
	 * this test because ExecPostprocessPlan might call us an extra time, and
	 * our subplan's nodes aren't necessarily robust against being called
	 * extra times.
	 */
	if (node->mt_done)
		return NULL;

	if (Gp_role == GP_ROLE_EXECUTE && !Gp_is_writer)
	{
		/*
		 * Current Cloudberry MPP architecture only support one writer gang, and
		 * only writer gang can execute DML nodes. There is no code path to reach
		 * here. For writable CTE case as below:
		 *
		 *   create table t(a int);
		 *   with wcte as (delete from t returning a)
		 *     insert into t select * from wcte;
		 *
		 * The above query will error out during parse-analyze so not reach here.
		 * If reaching here, some bugs must happen.
		 */