text: /*-------------------------------------------------------------------------
   *
   * nodeModifyTable.c
   *	  routines to handle ModifyTable nodes.
   *
   * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
   * Portions Copyright (c) 1994, Regents of the University of California
   *
   *
   * IDENTIFICATION
   *	  src/backend/executor/nodeModifyTable.c
   *
   *-------------------------------------------------------------------------
   */
  /* INTERFACE ROUTINES
   *		ExecInitModifyTable - initialize the ModifyTable node
   *		ExecModifyTable		- retrieve the next tuple from the node
   *		ExecEndModifyTable	- shut down the ModifyTable node
   *		ExecReScanModifyTable - rescan the ModifyTable node
   *
   *	 NOTES
   *		The ModifyTable node receives input from its outerPlan, which is
   *		the data to insert for INSERT cases, or the changed columns' new
   *		values plus row-locating info for UPDATE cases, or just the
   *		row-locating info for DELETE cases.
   *
   *		If the query specifies RETURNING, then the ModifyTable returns a
   *		RETURNING tuple after completing each row insert, update, or delete.
   *		It must be called again to continue the operation.  Without RETURNING,
   *		we just loop within the node until all the work is done, then
   *		return NULL.  This avoids useless call/return overhead.
   */
  
  #include "postgres.h"
  
  #include "access/heapam.h"
  #include "access/htup_details.h"
  #include "access/tableam.h"
  #include "access/xact.h"
  #include "catalog/catalog.h"
  #include "commands/trigger.h"
  #include "commands/defrem.h"
  #include "executor/execPartition.h"
  #include "executor/executor.h"
  #include "executor/nodeModifyTable.h"
  #include "executor/tstoreReceiver.h"
  #include "foreign/fdwapi.h"
  #include "miscadmin.h"
  #include "nodes/nodeFuncs.h"
  #include "parser/parser.h"
  #include "rewrite/rewriteHandler.h"
  #include "storage/bufmgr.h"
  #include "storage/lmgr.h"
  #include "utils/builtins.h"
  #include "utils/datum.h"
  #include "utils/memutils.h"
  #include "utils/rel.h"
  
  
  typedef struct MTTargetRelLookup
  {
  	Oid			relationOid;	/* hash key, must be first */
  	int			relationIndex;	/* rel's index in resultRelInfo[] array */
  } MTTargetRelLookup;
  
  static void ExecBatchInsert(ModifyTableState *mtstate,
  							ResultRelInfo *resultRelInfo,
  							TupleTableSlot **slots,
  							TupleTableSlot **planSlots,
  							int numSlots,
  							EState *estate,
  							bool canSetTag);
  static bool ExecOnConflictUpdate(ModifyTableState *mtstate,
  								 ResultRelInfo *resultRelInfo,
  								 ItemPointer conflictTid,
  								 TupleTableSlot *planSlot,
  								 TupleTableSlot *excludedSlot,
  								 EState *estate,
  								 bool canSetTag,
  								 TupleTableSlot **returning);
  static TupleTableSlot *ExecPrepareTupleRouting(ModifyTableState *mtstate,
  											   EState *estate,
  											   PartitionTupleRouting *proute,
  											   ResultRelInfo *targetRelInfo,
  											   TupleTableSlot *slot,
  											   ResultRelInfo **partRelInfo);
  
  /*
   * Verify that the tuples to be produced by INSERT match the
   * target relation's rowtype
   *
   * We do this to guard against stale plans.  If plan invalidation is
   * functioning properly then we should never get a failure here, but better
   * safe than sorry.  Note that this is called after we have obtained lock
   * on the target rel, so the rowtype can't change underneath us.
   *
   * The plan output is represented by its targetlist, because that makes
   * handling the dropped-column case easier.
   *
   * We used to use this for UPDATE as well, but now the equivalent checks
   * are done in ExecBuildUpdateProjection.
   */
  static void
  ExecCheckPlanOutput(Relation resultRel, List *targetList)
  {
  	TupleDesc	resultDesc = RelationGetDescr(resultRel);
  	int			attno = 0;
  	ListCell   *lc;
  
  	foreach(lc, targetList)
  	{
  		TargetEntry *tle = (TargetEntry *) lfirst(lc);
  		Form_pg_attribute attr;
  
  		Assert(!tle->resjunk);	/* caller removed junk items already */
  
  		if (attno >= resultDesc->natts)
  			ereport(ERROR,
  					(errcode(ERRCODE_DATATYPE_MISMATCH),
  					 errmsg("table row type and query-specified row type do not match"),
  					 errdetail("Query has too many columns.")));
  		attr = TupleDescAttr(resultDesc, attno);
  		attno++;
  
  		if (!attr->attisdropped)
  		{
  			/* Normal case: demand type match */
  			if (exprType((Node *) tle->expr) != attr->atttypid)
  				ereport(ERROR,
  						(errcode(ERRCODE_DATATYPE_MISMATCH),
  						 errmsg("table row type and query-specified row type do not match"),
  						 errdetail("Table has type %s at ordinal position %d, but query expects %s.",
  								   format_type_be(attr->atttypid),
  								   attno,
  								   format_type_be(exprType((Node *) tle->expr)))));
  		}
  		else
  		{
  			/*
  			 * For a dropped column, we can't check atttypid (it's likely 0).
  			 * In any case the planner has most likely inserted an INT4 null.
  			 * What we insist on is just *some* NULL constant.
  			 */
  			if (!IsA(tle->expr, Const) ||
  				!((Const *) tle->expr)->constisnull)
  				ereport(ERROR,
  						(errcode(ERRCODE_DATATYPE_MISMATCH),
  						 errmsg("table row type and query-specified row type do not match"),
  						 errdetail("Query provides a value for a dropped column at ordinal position %d.",
  								   attno)));
  		}
  	}
  	if (attno != resultDesc->natts)
  		ereport(ERROR,
  				(errcode(ERRCODE_DATATYPE_MISMATCH),
  				 errmsg("table row type and query-specified row type do not match"),
  				 errdetail("Query has too few columns.")));
  }
  
  /*
   * ExecProcessReturning --- evaluate a RETURNING list
   *
   * resultRelInfo: current result rel
   * tupleSlot: slot holding tuple actually inserted/updated/deleted
   * planSlot: slot holding tuple returned by top subplan node
   *
   * Note: If tupleSlot is NULL, the FDW should have already provided econtext's
   * scan tuple.
   *
   * Returns a slot holding the result tuple
   */
  static TupleTableSlot *
  ExecProcessReturning(ResultRelInfo *resultRelInfo,
  					 TupleTableSlot *tupleSlot,
  					 TupleTableSlot *planSlot)
  {
  	ProjectionInfo *projectReturning = resultRelInfo->ri_projectReturning;
  	ExprContext *econtext = projectReturning->pi_exprContext;
  
  	/* Make tuple and any needed join variables available to ExecProject */
  	if (tupleSlot)
  		econtext->ecxt_scantuple = tupleSlot;
  	econtext->ecxt_outertuple = planSlot;
  
  	/*
  	 * RETURNING expressions might reference the tableoid column, so
  	 * reinitialize tts_tableOid before evaluating them.
  	 */
  	econtext->ecxt_scantuple->tts_tableOid =
  		RelationGetRelid(resultRelInfo->ri_RelationDesc);
  
  	/* Compute the RETURNING expressions */
  	return ExecProject(projectReturning);
  }
  
  /*
   * ExecCheckTupleVisible -- verify tuple is visible
   *
   * It would not be consistent with guarantees of the higher isolation levels to
   * proceed with avoiding insertion (taking speculative insertion's alternative
   * path) on the basis of another tuple that is not visible to MVCC snapshot.
   * Check for the need to raise a serialization failure, and do so as necessary.
   */
  static void
  ExecCheckTupleVisible(EState *estate,
  					  Relation rel,
  					  TupleTableSlot *slot)
  {
  	if (!IsolationUsesXactSnapshot())
  		return;
  
  	if (!table_tuple_satisfies_snapshot(rel, slot, estate->es_snapshot))
  	{
  		Datum		xminDatum;
  		TransactionId xmin;
  		bool		isnull;
  
  		xminDatum = slot_getsysattr(slot, MinTransactionIdAttributeNumber, &isnull);
  		Assert(!isnull);
  		xmin = DatumGetTransactionId(xminDatum);
  
  		/*
  		 * We should not raise a serialization failure if the conflict is
  		 * against a tuple inserted by our own transaction, even if it's not
  		 * visible to our snapshot.  (This would happen, for example, if
  		 * conflicting keys are proposed for insertion in a single command.)
  		 */
  		if (!TransactionIdIsCurrentTransactionId(xmin))
  			ereport(ERROR,
  					(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
  					 errmsg("could not serialize access due to concurrent update")));
  	}
  }
  
  /*
   * ExecCheckTIDVisible -- convenience variant of ExecCheckTupleVisible()
   */
  static void
  ExecCheckTIDVisible(EState *estate,
  					ResultRelInfo *relinfo,
  					ItemPointer tid,
  					TupleTableSlot *tempSlot)
  {
  	Relation	rel = relinfo->ri_RelationDesc;
  
  	/* Redundantly check isolation level */
  	if (!IsolationUsesXactSnapshot())
  		return;
  
  	if (!table_tuple_fetch_row_version(rel, tid, SnapshotAny, tempSlot))
  		elog(ERROR, "failed to fetch conflicting tuple for ON CONFLICT");
  	ExecCheckTupleVisible(estate, rel, tempSlot);
  	ExecClearTuple(tempSlot);
  }
  
  /*
   * Compute stored generated columns for a tuple
   */
  void
  ExecComputeStoredGenerated(ResultRelInfo *resultRelInfo,
  						   EState *estate, TupleTableSlot *slot,
  						   CmdType cmdtype)
  {
  	Relation	rel = resultRelInfo->ri_RelationDesc;
  	TupleDesc	tupdesc = RelationGetDescr(rel);
  	int			natts = tupdesc->natts;
  	MemoryContext oldContext;
  	Datum	   *values;
  	bool	   *nulls;
  
  	Assert(tupdesc->constr && tupdesc->constr->has_generated_stored);
  
  	/*
  	 * If first time through for this result relation, build expression
  	 * nodetrees for rel's stored generation expressions.  Keep them in the
  	 * per-query memory context so they'll survive throughout the query.
  	 */
  	if (resultRelInfo->ri_GeneratedExprs == NULL)
  	{
  		oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
  
  		resultRelInfo->ri_GeneratedExprs =
  			(ExprState **) palloc(natts * sizeof(ExprState *));
  		resultRelInfo->ri_NumGeneratedNeeded = 0;
  
  		for (int i = 0; i < natts; i++)
  		{
  			if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_STORED)
  			{
  				Expr	   *expr;
  
  				/*
  				 * If it's an update and the current column was not marked as
  				 * being updated, then we can skip the computation.  But if
  				 * there is a BEFORE ROW UPDATE trigger, we cannot skip
  				 * because the trigger might affect additional columns.
  				 */
  				if (cmdtype == CMD_UPDATE &&
  					!(rel->trigdesc && rel->trigdesc->trig_update_before_row) &&
  					!bms_is_member(i + 1 - FirstLowInvalidHeapAttributeNumber,
  								   ExecGetExtraUpdatedCols(resultRelInfo, estate)))
  				{
  					resultRelInfo->ri_GeneratedExprs[i] = NULL;
  					continue;
  				}
  
  				expr = (Expr *) build_column_default(rel, i + 1);
  				if (expr == NULL)
  					elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
  						 i + 1, RelationGetRelationName(rel));
  
  				resultRelInfo->ri_GeneratedExprs[i] = ExecPrepareExpr(expr, estate);
  				resultRelInfo->ri_NumGeneratedNeeded++;
  			}
  		}
  
  		MemoryContextSwitchTo(oldContext);
  	}
  
  	/*
  	 * If no generated columns have been affected by this change, then skip
  	 * the rest.
  	 */
  	if (resultRelInfo->ri_NumGeneratedNeeded == 0)
  		return;
  
  	oldContext = MemoryContextSwitchTo(GetPerTupleMemoryContext(estate));
  
  	values = palloc(sizeof(*values) * natts);
  	nulls = palloc(sizeof(*nulls) * natts);
  
  	slot_getallattrs(slot);
  	memcpy(nulls, slot->tts_isnull, sizeof(*nulls) * natts);
  
  	for (int i = 0; i < natts; i++)
  	{
  		Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
  
  		if (attr->attgenerated == ATTRIBUTE_GENERATED_STORED &&
  			resultRelInfo->ri_GeneratedExprs[i])
  		{
  			ExprContext *econtext;
  			Datum		val;
  			bool		isnull;
  
  			econtext = GetPerTupleExprContext(estate);
  			econtext->ecxt_scantuple = slot;
  
  			val = ExecEvalExpr(resultRelInfo->ri_GeneratedExprs[i], econtext, &isnull);
  
  			/*
  			 * We must make a copy of val as we have no guarantees about where
  			 * memory for a pass-by-reference Datum is located.
  			 */
  			if (!isnull)
  				val = datumCopy(val, attr->attbyval, attr->attlen);
  
  			values[i] = val;
  			nulls[i] = isnull;
  		}
  		else
  		{
  			if (!nulls[i])
  				values[i] = datumCopy(slot->tts_values[i], attr->attbyval, attr->attlen);
  		}
  	}
  
  	ExecClearTuple(slot);
  	memcpy(slot->tts_values, values, sizeof(*values) * natts);
  	memcpy(slot->tts_isnull, nulls, sizeof(*nulls) * natts);
  	ExecStoreVirtualTuple(slot);
  	ExecMaterializeSlot(slot);
  
  	MemoryContextSwitchTo(oldContext);
  }
  
  /*
   * ExecInitInsertProjection
   *		Do one-time initialization of projection data for INSERT tuples.
   *
   * INSERT queries may need a projection to filter out junk attrs in the tlist.
   *
   * This is also a convenient place to verify that the
   * output of an INSERT matches the target table.
   */
  static void
  ExecInitInsertProjection(ModifyTableState *mtstate,
  						 ResultRelInfo *resultRelInfo)
  {
  	ModifyTable *node = (ModifyTable *) mtstate->ps.plan;
  	Plan	   *subplan = outerPlan(node);
  	EState	   *estate = mtstate->ps.state;
  	List	   *insertTargetList = NIL;
  	bool		need_projection = false;
  	ListCell   *l;
  
  	/* Extract non-junk columns of the subplan's result tlist. */
  	foreach(l, subplan->targetlist)
  	{
  		TargetEntry *tle = (TargetEntry *) lfirst(l);
  
  		if (!tle->resjunk)
  			insertTargetList = lappend(insertTargetList, tle);
  		else
  			need_projection = true;
  	}
  
  	/*
  	 * The junk-free list must produce a tuple suitable for the result
  	 * relation.
  	 */
  	ExecCheckPlanOutput(resultRelInfo->ri_RelationDesc, insertTargetList);
  
  	/* We'll need a slot matching the table's format. */
  	resultRelInfo->ri_newTupleSlot =
  		table_slot_create(resultRelInfo->ri_RelationDesc,
  						  &estate->es_tupleTable);
  
  	/* Build ProjectionInfo if needed (it probably isn't). */
  	if (need_projection)
  	{
  		TupleDesc	relDesc = RelationGetDescr(resultRelInfo->ri_RelationDesc);
  
  		/* need an expression context to do the projection */
  		if (mtstate->ps.ps_ExprContext == NULL)
  			ExecAssignExprContext(estate, &mtstate->ps);
  
  		resultRelInfo->ri_projectNew =
  			ExecBuildProjectionInfo(insertTargetList,
  									mtstate->ps.ps_ExprContext,
  									resultRelInfo->ri_newTupleSlot,
  									&mtstate->ps,
  									relDesc);
  	}
  
  	resultRelInfo->ri_projectNewInfoValid = true;
  }
  
  /*
   * ExecInitUpdateProjection
   *		Do one-time initialization of projection data for UPDATE tuples.
   *
   * UPDATE always needs a projection, because (1) there's always some junk
   * attrs, and (2) we may need to merge values of not-updated columns from
   * the old tuple into the final tuple.  In UPDATE, the tuple arriving from
   * the subplan contains only new values for the changed columns, plus row
   * identity info in the junk attrs.
   *
   * This is "one-time" for any given result rel, but we might touch more than
   * one result rel in the course of an inherited UPDATE, and each one needs
   * its own projection due to possible column order variation.
   *
   * This is also a convenient place to verify that the output of an UPDATE
   * matches the target table (ExecBuildUpdateProjection does that).
   */
  static void
  ExecInitUpdateProjection(ModifyTableState *mtstate,
  						 ResultRelInfo *resultRelInfo)
  {
  	ModifyTable *node = (ModifyTable *) mtstate->ps.plan;
  	Plan	   *subplan = outerPlan(node);
  	EState	   *estate = mtstate->ps.state;
  	TupleDesc	relDesc = RelationGetDescr(resultRelInfo->ri_RelationDesc);
  	int			whichrel;
  	List	   *updateColnos;
  
  	/*
  	 * Usually, mt_lastResultIndex matches the target rel.  If it happens not
  	 * to, we can get the index the hard way with an integer division.
  	 */
  	whichrel = mtstate->mt_lastResultIndex;
  	if (resultRelInfo != mtstate->resultRelInfo + whichrel)
  	{
  		whichrel = resultRelInfo - mtstate->resultRelInfo;
  		Assert(whichrel >= 0 && whichrel < mtstate->mt_nrels);
  	}
  
  	updateColnos = (List *) list_nth(node->updateColnosLists, whichrel);
  
  	/*
  	 * For UPDATE, we use the old tuple to fill up missing values in the tuple
  	 * produced by the subplan to get the new tuple.  We need two slots, both
  	 * matching the table's desired format.
  	 */
  	resultRelInfo->ri_oldTupleSlot =
  		table_slot_create(resultRelInfo->ri_RelationDesc,
  						  &estate->es_tupleTable);
  	resultRelInfo->ri_newTupleSlot =
  		table_slot_create(resultRelInfo->ri_RelationDesc,
  						  &estate->es_tupleTable);
  
  	/* need an expression context to do the projection */
  	if (mtstate->ps.ps_ExprContext == NULL)
  		ExecAssignExprContext(estate, &mtstate->ps);
  
  	resultRelInfo->ri_projectNew =
  		ExecBuildUpdateProjection(subplan->targetlist,
  								  false,	/* subplan did the evaluation */
  								  updateColnos,
  								  relDesc,
  								  mtstate->ps.ps_ExprContext,
  								  resultRelInfo->ri_newTupleSlot,
  								  &mtstate->ps);
  
  	resultRelInfo->ri_projectNewInfoValid = true;
  }
  
  /*
   * ExecGetInsertNewTuple
   *		This prepares a "new" tuple ready to be inserted into given result
   *		relation, by removing any junk columns of the plan's output tuple
   *		and (if necessary) coercing the tuple to the right tuple format.
   */
  static TupleTableSlot *
  ExecGetInsertNewTuple(ResultRelInfo *relinfo,
  					  TupleTableSlot *planSlot)
  {
  	ProjectionInfo *newProj = relinfo->ri_projectNew;
  	ExprContext *econtext;
  
  	/*
  	 * If there's no projection to be done, just make sure the slot is of the
  	 * right type for the target rel.  If the planSlot is the right type we
  	 * can use it as-is, else copy the data into ri_newTupleSlot.
  	 */
  	if (newProj == NULL)
  	{
  		if (relinfo->ri_newTupleSlot->tts_ops != planSlot->tts_ops)
  		{
  			ExecCopySlot(relinfo->ri_newTupleSlot, planSlot);
  			return relinfo->ri_newTupleSlot;
  		}
  		else
  			return planSlot;
  	}
  
  	/*
  	 * Else project; since the projection output slot is ri_newTupleSlot, this
  	 * will also fix any slot-type problem.
  	 *
  	 * Note: currently, this is dead code, because INSERT cases don't receive
  	 * any junk columns so there's never a projection to be done.
  	 */
  	econtext = newProj->pi_exprContext;
  	econtext->ecxt_outertuple = planSlot;
  	return ExecProject(newProj);
  }
  
  /*
   * ExecGetUpdateNewTuple
   *		This prepares a "new" tuple by combining an UPDATE subplan's output
   *		tuple (which contains values of changed columns) with unchanged
   *		columns taken from the old tuple.
   *
   * The subplan tuple might also contain junk columns, which are ignored.
   * Note that the projection also ensures we have a slot of the right type.
   */
  TupleTableSlot *
  ExecGetUpdateNewTuple(ResultRelInfo *relinfo,
  					  TupleTableSlot *planSlot,
  					  TupleTableSlot *oldSlot)
  {
  	ProjectionInfo *newProj = relinfo->ri_projectNew;
  	ExprContext *econtext;
  
  	/* Use a few extra Asserts to protect against outside callers */
  	Assert(relinfo->ri_projectNewInfoValid);
  	Assert(planSlot != NULL && !TTS_EMPTY(planSlot));
  	Assert(oldSlot != NULL && !TTS_EMPTY(oldSlot));
  
  	econtext = newProj->pi_exprContext;
  	econtext->ecxt_outertuple = planSlot;
  	econtext->ecxt_scantuple = oldSlot;
  	return ExecProject(newProj);
  }
  
  
  /* ----------------------------------------------------------------
   *		ExecInsert
   *
   *		For INSERT, we have to insert the tuple into the target relation
   *		(or partition thereof) and insert appropriate tuples into the index
   *		relations.
   *
   *		slot contains the new tuple value to be stored.
   *		planSlot is the output of the ModifyTable's subplan; we use it
   *		to access "junk" columns that are not going to be stored.
   *
   *		Returns RETURNING result if any, otherwise NULL.
   *
   *		This may change the currently active tuple conversion map in
   *		mtstate->mt_transition_capture, so the callers must take care to
   *		save the previous value to avoid losing track of it.
   * ----------------------------------------------------------------
   */
  static TupleTableSlot *
  ExecInsert(ModifyTableState *mtstate,
  		   ResultRelInfo *resultRelInfo,
  		   TupleTableSlot *slot,
  		   TupleTableSlot *planSlot,
  		   EState *estate,
  		   bool canSetTag)
  {
  	Relation	resultRelationDesc;
  	List	   *recheckIndexes = NIL;
  	TupleTableSlot *result = NULL;
  	TransitionCaptureState *ar_insert_trig_tcs;
  	ModifyTable *node = (ModifyTable *) mtstate->ps.plan;
  	OnConflictAction onconflict = node->onConflictAction;
  	PartitionTupleRouting *proute = mtstate->mt_partition_tuple_routing;
  	MemoryContext oldContext;
  
  	/*
  	 * If the input result relation is a partitioned table, find the leaf
  	 * partition to insert the tuple into.
  	 */
  	if (proute)
  	{
  		ResultRelInfo *partRelInfo;
  
  		slot = ExecPrepareTupleRouting(mtstate, estate, proute,
  									   resultRelInfo, slot,
  									   &partRelInfo);
  		resultRelInfo = partRelInfo;
  	}
  
  	ExecMaterializeSlot(slot);
  
  	resultRelationDesc = resultRelInfo->ri_RelationDesc;
  
  	/*
  	 * Open the table's indexes, if we have not done so already, so that we
  	 * can add new index entries for the inserted tuple.
  	 */
  	if (resultRelationDesc->rd_rel->relhasindex &&
  		resultRelInfo->ri_IndexRelationDescs == NULL)
  		ExecOpenIndices(resultRelInfo, onconflict != ONCONFLICT_NONE);
  
  	/*
  	 * BEFORE ROW INSERT Triggers.
  	 *
  	 * Note: We fire BEFORE ROW TRIGGERS for every attempted insertion in an
  	 * INSERT ... ON CONFLICT statement.  We cannot check for constraint
  	 * violations before firing these triggers, because they can change the
  	 * values to insert.  Also, they can run arbitrary user-defined code with
  	 * side-effects that we can't cancel by just not inserting the tuple.
  	 */
  	if (resultRelInfo->ri_TrigDesc &&
  		resultRelInfo->ri_TrigDesc->trig_insert_before_row)
  	{
  		if (!ExecBRInsertTriggers(estate, resultRelInfo, slot))
  			return NULL;		/* "do nothing" */
  	}
  
  	/* Process RETURNING if present */
  	if (resultRelInfo->ri_projectReturning)
  		result = ExecProcessReturning(resultRelInfo, slot, planSlot);
  
  	/* INSTEAD OF ROW INSERT Triggers */
  	if (resultRelInfo->ri_TrigDesc &&
  		resultRelInfo->ri_TrigDesc->trig_insert_instead_row)
  	{
  		if (!ExecIRInsertTriggers(estate, resultRelInfo, slot))
  			return NULL;		/* "do nothing" */
  	}
  	else if (sql_dialect == SQL_DIALECT_TSQL && resultRelInfo->ri_TrigDesc &&
  		resultRelInfo->ri_TrigDesc->trig_insert_instead_statement){
  		ExecIRInsertTriggersTSQL(estate, resultRelInfo, slot, mtstate->mt_transition_capture);
  		// if it's a statement level IOT trigger, only get the transition table
  		return NULL;
  	}
  	else if (resultRelInfo->ri_FdwRoutine)
  	{
  		/*
  		 * GENERATED expressions might reference the tableoid column, so
  		 * (re-)initialize tts_tableOid before evaluating them.
  		 */
  		slot->tts_tableOid = RelationGetRelid(resultRelInfo->ri_RelationDesc);
  
  		/*
  		 * Compute stored generated columns
  		 */
  		if (resultRelationDesc->rd_att->constr &&
  			resultRelationDesc->rd_att->constr->has_generated_stored)
  			ExecComputeStoredGenerated(resultRelInfo, estate, slot,
  									   CMD_INSERT);
  
  		/*
  		 * If the FDW supports batching, and batching is requested, accumulate
  		 * rows and insert them in batches. Otherwise use the per-row inserts.
  		 */
  		if (resultRelInfo->ri_BatchSize > 1)
  		{
  			/*
  			 * If a certain number of tuples have already been accumulated, or
  			 * a tuple has come for a different relation than that for the
  			 * accumulated tuples, perform the batch insert
  			 */
  			if (resultRelInfo->ri_NumSlots == resultRelInfo->ri_BatchSize)
  			{
  				ExecBatchInsert(mtstate, resultRelInfo,
  								resultRelInfo->ri_Slots,
  								resultRelInfo->ri_PlanSlots,
  								resultRelInfo->ri_NumSlots,
  								estate, canSetTag);
  				resultRelInfo->ri_NumSlots = 0;
  			}
  
  			oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
  
  			if (resultRelInfo->ri_Slots == NULL)
  			{
  				resultRelInfo->ri_Slots = palloc(sizeof(TupleTableSlot *) *
  												 resultRelInfo->ri_BatchSize);
  				resultRelInfo->ri_PlanSlots = palloc(sizeof(TupleTableSlot *) *
  													 resultRelInfo->ri_BatchSize);
  			}
  
  			/*
  			 * Initialize the batch slots. We don't know how many slots will
  			 * be needed, so we initialize them as the batch grows, and we
  			 * keep them across batches. To mitigate an inefficiency in how
  			 * resource owner handles objects with many references (as with
  			 * many slots all referencing the same tuple descriptor) we copy
  			 * the appropriate tuple descriptor for each slot.
  			 */
  			if (resultRelInfo->ri_NumSlots >= resultRelInfo->ri_NumSlotsInitialized)
  			{
  				TupleDesc	tdesc = CreateTupleDescCopy(slot->tts_tupleDescriptor);
  				TupleDesc	plan_tdesc =
  					CreateTupleDescCopy(planSlot->tts_tupleDescriptor);
  
  				resultRelInfo->ri_Slots[resultRelInfo->ri_NumSlots] =
  					MakeSingleTupleTableSlot(tdesc, slot->tts_ops);
  
  				resultRelInfo->ri_PlanSlots[resultRelInfo->ri_NumSlots] =
  					MakeSingleTupleTableSlot(plan_tdesc, planSlot->tts_ops);
  
  				/* remember how many batch slots we initialized */
  				resultRelInfo->ri_NumSlotsInitialized++;
  			}
  
  			ExecCopySlot(resultRelInfo->ri_Slots[resultRelInfo->ri_NumSlots],
  						 slot);
  
  			ExecCopySlot(resultRelInfo->ri_PlanSlots[resultRelInfo->ri_NumSlots],
  						 planSlot);
  
  			resultRelInfo->ri_NumSlots++;
  
  			MemoryContextSwitchTo(oldContext);
  
  			return NULL;
  		}
  
  		/*
  		 * insert into foreign table: let the FDW do it
  		 */
  		slot = resultRelInfo->ri_FdwRoutine->ExecForeignInsert(estate,
  															   resultRelInfo,
  															   slot,
  															   planSlot);
  
  		if (slot == NULL)		/* "do nothing" */
  			return NULL;
  
  		/*
  		 * AFTER ROW Triggers or RETURNING expressions might reference the
  		 * tableoid column, so (re-)initialize tts_tableOid before evaluating
  		 * them.  (This covers the case where the FDW replaced the slot.)
  		 */
  		slot->tts_tableOid = RelationGetRelid(resultRelInfo->ri_RelationDesc);
  	}
  	else
  	{
  		WCOKind		wco_kind;
  
  		/*
  		 * Constraints and GENERATED expressions might reference the tableoid
  		 * column, so (re-)initialize tts_tableOid before evaluating them.
  		 */
  		slot->tts_tableOid = RelationGetRelid(resultRelationDesc);
  
  		/*
  		 * Compute stored generated columns
  		 */
  		if (resultRelationDesc->rd_att->constr &&
  			resultRelationDesc->rd_att->constr->has_generated_stored)
  			ExecComputeStoredGenerated(resultRelInfo, estate, slot,
  									   CMD_INSERT);
  
  		/*
  		 * Check any RLS WITH CHECK policies.
  		 *
  		 * Normally we should check INSERT policies. But if the insert is the
  		 * result of a partition key update that moved the tuple to a new
  		 * partition, we should instead check UPDATE policies, because we are
  		 * executing policies defined on the target table, and not those
  		 * defined on the child partitions.
  		 */
  		wco_kind = (mtstate->operation == CMD_UPDATE) ?
  			WCO_RLS_UPDATE_CHECK : WCO_RLS_INSERT_CHECK;
  
  		/*
  		 * ExecWithCheckOptions() will skip any WCOs which are not of the kind
  		 * we are looking for at this point.
  		 */
  		if (resultRelInfo->ri_WithCheckOptions != NIL)
  			ExecWithCheckOptions(wco_kind, resultRelInfo, slot, estate);
  
  		/*
  		 * Check the constraints of the tuple.
  		 */
  		if (resultRelationDesc->rd_att->constr)
  			ExecConstraints(resultRelInfo, slot, estate);
  
  		/*
  		 * Also check the tuple against the partition constraint, if there is
  		 * one; except that if we got here via tuple-routing, we don't need to
  		 * if there's no BR trigger defined on the partition.
  		 */
  		if (resultRelationDesc->rd_rel->relispartition &&
  			(resultRelInfo->ri_RootResultRelInfo == NULL ||
  			 (resultRelInfo->ri_TrigDesc &&
  			  resultRelInfo->ri_TrigDesc->trig_insert_before_row)))
  			ExecPartitionCheck(resultRelInfo, slot, estate, true);
  
  		if (onconflict != ONCONFLICT_NONE && resultRelInfo->ri_NumIndices > 0)
  		{
  			/* Perform a speculative insertion. */
  			uint32		specToken;
  			ItemPointerData conflictTid;
  			bool		specConflict;
  			List	   *arbiterIndexes;
  
  			arbiterIndexes = resultRelInfo->ri_onConflictArbiterIndexes;
  
  			/*
  			 * Do a non-conclusive check for conflicts first.
  			 *
  			 * We're not holding any locks yet, so this doesn't guarantee that
  			 * the later insert won't conflict.  But it avoids leaving behind
  			 * a lot of canceled speculative insertions, if you run a lot of
  			 * INSERT ON CONFLICT statements that do conflict.
  			 *
  			 * We loop back here if we find a conflict below, either during
  			 * the pre-check, or when we re-check after inserting the tuple
  			 * speculatively.
  			 */
  	vlock:
  			specConflict = false;
  			if (!ExecCheckIndexConstraints(resultRelInfo, slot, estate,
  										   &conflictTid, arbiterIndexes))
  			{
  				/* committed conflict tuple found */
  				if (onconflict == ONCONFLICT_UPDATE)
  				{
  					/*
  					 * In case of ON CONFLICT DO UPDATE, execute the UPDATE
  					 * part.  Be prepared to retry if the UPDATE fails because
  					 * of another concurrent UPDATE/DELETE to the conflict
  					 * tuple.
  					 */
  					TupleTableSlot *returning = NULL;
  
  					if (ExecOnConflictUpdate(mtstate, resultRelInfo,
  											 &conflictTid, planSlot, slot,
  											 estate, canSetTag, &returning))
  					{
  						InstrCountTuples2(&mtstate->ps, 1);
  						return returning;
  					}
  					else
  						goto vlock;
  				}
  				else
  				{
  					/*
  					 * In case of ON CONFLICT DO NOTHING, do nothing. However,
  					 * verify that the tuple is visible to the executor's MVCC
  					 * snapshot at higher isolation levels.
  					 *
  					 * Using ExecGetReturningSlot() to store the tuple for the
  					 * recheck isn't that pretty, but we can't trivially use
  					 * the input slot, because it might not be of a compatible
  					 * type. As there's no conflicting usage of
  					 * ExecGetReturningSlot() in the DO NOTHING case...
  					 */
  					Assert(onconflict == ONCONFLICT_NOTHING);
  					ExecCheckTIDVisible(estate, resultRelInfo, &conflictTid,
  										ExecGetReturningSlot(estate, resultRelInfo));
  					InstrCountTuples2(&mtstate->ps, 1);
  					return NULL;
  				}
  			}
  
  			/*
  			 * Before we start insertion proper, acquire our "speculative
  			 * insertion lock".  Others can use that to wait for us to decide
  			 * if we're going to go ahead with the insertion, instead of
  			 * waiting for the whole transaction to complete.
  			 */
  			specToken = SpeculativeInsertionLockAcquire(GetCurrentTransactionId());
  
  			/* insert the tuple, with the speculative token */
  			table_tuple_insert_speculative(resultRelationDesc, slot,
  										   estate->es_output_cid,
  										   0,
  										   NULL,
  										   specToken);
  
  			/* insert index entries for tuple */
  			recheckIndexes = ExecInsertIndexTuples(resultRelInfo,
  												   slot, estate, false, true,
  												   &specConflict,
  												   arbiterIndexes);
  
  			/* adjust the tuple's state accordingly */
  			table_tuple_complete_speculative(resultRelationDesc, slot,
  											 specToken, !specConflict);
  
  			/*
  			 * Wake up anyone waiting for our decision.  They will re-check
  			 * the tuple, see that it's no longer speculative, and wait on our
  			 * XID as if this was a regularly inserted tuple all along.  Or if
  			 * we killed the tuple, they will see it's dead, and proceed as if
  			 * the tuple never existed.
  			 */
  			SpeculativeInsertionLockRelease(GetCurrentTransactionId());
  
  			/*
  			 * If there was a conflict, start from the beginning.  We'll do
  			 * the pre-check again, which will now find the conflicting tuple
  			 * (unless it aborts before we get there).
  			 */
  			if (specConflict)
  			{
  				list_free(recheckIndexes);
  				goto vlock;
  			}
  
  			/* Since there was no insertion conflict, we're done */
  		}
  		else
  		{
  			/* insert the tuple normally */
  			table_tuple_insert(resultRelationDesc, slot,
  							   estate->es_output_cid,
  							   0, NULL);
  
  			/* insert index entries for tuple */
  			if (resultRelInfo->ri_NumIndices > 0)
  				recheckIndexes = ExecInsertIndexTuples(resultRelInfo,
  													   slot, estate, false,
  													   false, NULL, NIL);
  		}
  	}
  
  	if (canSetTag)
  		(estate->es_processed)++;
  
  	/*
  	 * If this insert is the result of a partition key update that moved the
  	 * tuple to a new partition, put this row into the transition NEW TABLE,
  	 * if there is one. We need to do this separately for DELETE and INSERT
  	 * because they happen on different tables.
  	 */
  	ar_insert_trig_tcs = mtstate->mt_transition_capture;
  	if (mtstate->operation == CMD_UPDATE && mtstate->mt_transition_capture
  		&& mtstate->mt_transition_capture->tcs_update_new_table)
  	{
  		ExecARUpdateTriggers(estate, resultRelInfo, NULL,
  							 NULL,
  							 slot,
  							 NULL,
  							 mtstate->mt_transition_capture);
  
  		/*
  		 * We've already captured the NEW TABLE row, so make sure any AR
  		 * INSERT trigger fired below doesn't capture it again.
  		 */
  		ar_insert_trig_tcs = NULL;
  	}
  
  	/* AFTER ROW INSERT Triggers */
  	ExecARInsertTriggers(estate, resultRelInfo, slot, recheckIndexes,
  						 ar_insert_trig_tcs);
  
  	list_free(recheckIndexes);
  
  	/*
  	 * Check any WITH CHECK OPTION constraints from parent views.  We are
  	 * required to do this after testing all constraints and uniqueness
  	 * violations per the SQL spec, so we do it after actually inserting the
  	 * record into the heap and all indexes.
  	 *
  	 * ExecWithCheckOptions will elog(ERROR) if a violation is found, so the
  	 * tuple will never be seen, if it violates the WITH CHECK OPTION.
  	 *
  	 * ExecWithCheckOptions() will skip any WCOs which are not of the kind we
  	 * are looking for at this point.
  	 */
  	if (resultRelInfo->ri_WithCheckOptions != NIL)
  		ExecWithCheckOptions(WCO_VIEW_CHECK, resultRelInfo, slot, estate);
  
  	/* Process RETURNING if present */
  	if (resultRelInfo->ri_projectReturning)
  		result = ExecProcessReturning(resultRelInfo, slot, planSlot);
  
  	return result;
  }
  
  /* ----------------------------------------------------------------
   *		ExecBatchInsert
   *
   *		Insert multiple tuples in an efficient way.
   *		Currently, this handles inserting into a foreign table without
   *		RETURNING clause.
   * ----------------------------------------------------------------
   */
  static void
  ExecBatchInsert(ModifyTableState *mtstate,
  				ResultRelInfo *resultRelInfo,
  				TupleTableSlot **slots,
  				TupleTableSlot **planSlots,
  				int numSlots,
  				EState *estate,
  				bool canSetTag)
  {
  	int			i;
  	int			numInserted = numSlots;
  	TupleTableSlot *slot = NULL;
  	TupleTableSlot **rslots;
  
  	/*
  	 * insert into foreign table: let the FDW do it
  	 */
  	rslots = resultRelInfo->ri_FdwRoutine->ExecForeignBatchInsert(estate,
  																  resultRelInfo,
  																  slots,
  																  planSlots,
  																  &numInserted);
  
  	for (i = 0; i < numInserted; i++)
  	{
  		slot = rslots[i];
  
  		/*
  		 * AFTER ROW Triggers or RETURNING expressions might reference the
  		 * tableoid column, so (re-)initialize tts_tableOid before evaluating
  		 * them.
  		 */
  		slot->tts_tableOid = RelationGetRelid(resultRelInfo->ri_RelationDesc);
  
  		/* AFTER ROW INSERT Triggers */
  		ExecARInsertTriggers(estate, resultRelInfo, slot, NIL,
  							 mtstate->mt_transition_capture);
  
  		/*
  		 * Check any WITH CHECK OPTION constraints from parent views.  See the
  		 * comment in ExecInsert.
  		 */
  		if (resultRelInfo->ri_WithCheckOptions != NIL)
  			ExecWithCheckOptions(WCO_VIEW_CHECK, resultRelInfo, slot, estate);
  	}
  
  	if (canSetTag && numInserted > 0)
  		estate->es_processed += numInserted;
  }
  
  /* ----------------------------------------------------------------
   *		ExecDelete
   *
   *		DELETE is like UPDATE, except that we delete the tuple and no
   *		index modifications are needed.
   *
   *		When deleting from a table, tupleid identifies the tuple to
   *		delete and oldtuple is NULL.  When deleting from a view,
   *		oldtuple is passed to the INSTEAD OF triggers and identifies
   *		what to delete, and tupleid is invalid.  When deleting from a
   *		foreign table, tupleid is invalid; the FDW has to figure out
   *		which row to delete using data from the planSlot.  oldtuple is
   *		passed to foreign table triggers; it is NULL when the foreign
   *		table has no relevant triggers.  We use tupleDeleted to indicate
   *		whether the tuple is actually deleted, callers can use it to
   *		decide whether to continue the operation.  When this DELETE is a
   *		part of an UPDATE of partition-key, then the slot returned by
   *		EvalPlanQual() is passed back using output parameter epqslot.
   *
   *		Returns RETURNING result if any, otherwise NULL.
   * ----------------------------------------------------------------
   */
  static TupleTableSlot *
  ExecDelete(ModifyTableState *mtstate,
  		   ResultRelInfo *resultRelInfo,
  		   ItemPointer tupleid,
  		   HeapTuple oldtuple,
  		   TupleTableSlot *planSlot,
  		   EPQState *epqstate,
  		   EState *estate,
  		   bool processReturning,
  		   bool canSetTag,
  		   bool changingPart,
  		   bool *tupleDeleted,
  		   TupleTableSlot **epqreturnslot)
  {
  	Relation	resultRelationDesc = resultRelInfo->ri_RelationDesc;
  	TM_Result	result;
  	TM_FailureData tmfd;
  	TupleTableSlot *slot = NULL;
  	TransitionCaptureState *ar_delete_trig_tcs;
  	TupleTableSlot *rslot_output = NULL;
  
  	if (tupleDeleted)
  		*tupleDeleted = false;
  
  	/* BEFORE ROW DELETE Triggers */
  	if (resultRelInfo->ri_TrigDesc &&
  		resultRelInfo->ri_TrigDesc->trig_delete_before_row)
  	{
  		bool		dodelete;
  
  		dodelete = ExecBRDeleteTriggers(estate, epqstate, resultRelInfo,
  										tupleid, oldtuple, epqreturnslot);
  
  		if (!dodelete)			/* "do nothing" */
  			return NULL;
  	}
  
  	/* Process RETURNING if present and if requested */
  	if (processReturning && resultRelInfo->ri_projectReturning && sql_dialect == SQL_DIALECT_TSQL)
  	{
  		/*
  		 * We have to put the target tuple into a slot, which means first we
  		 * gotta fetch it.  We can use the trigger tuple slot.
  		 */
  		if (resultRelInfo->ri_FdwRoutine)
  		{
  			/* FDW must have provided a slot containing the deleted row */
  			Assert(!TupIsNull(slot));
  		}
  		else
  		{
  			slot = ExecGetReturningSlot(estate, resultRelInfo);
  			if (oldtuple != NULL)
  			{
  				ExecForceStoreHeapTuple(oldtuple, slot, false);
  			}
  			else
  			{
  				if (!table_tuple_fetch_row_version(resultRelationDesc, tupleid,
  												   SnapshotAny, slot))
  					elog(ERROR, "failed to fetch deleted tuple for DELETE RETURNING");
  			}
  		}
  		rslot_output = ExecProcessReturning(resultRelInfo, slot, planSlot);
  
  		/*
  		 * Before releasing the target tuple again, make sure rslot has a
  		 * local copy of any pass-by-reference values.
  		 */
  		ExecMaterializeSlot(rslot_output);
  
  		ExecClearTuple(slot);
  	}
  
  	if (resultRelInfo->ri_TrigDesc &&
  		resultRelInfo->ri_TrigDesc->trig_delete_instead_statement &&
  		sql_dialect == SQL_DIALECT_TSQL && 
  		isTsqlInsteadofTriggerExecution(estate, resultRelInfo, TRIGGER_EVENT_DELETE))
  	{
  		ExecIRDeleteTriggersTSQL(estate, resultRelInfo, tupleid, oldtuple, mtstate->mt_transition_capture);
  		return NULL;
  	}
  
  	/* INSTEAD OF ROW DELETE Triggers */
  	if (resultRelInfo->ri_TrigDesc &&
  		resultRelInfo->ri_TrigDesc->trig_delete_instead_row)
  	{
  		bool		dodelete;
  
  		Assert(oldtuple != NULL);
  		dodelete = ExecIRDeleteTriggers(estate, resultRelInfo, oldtuple);
  
  		if (!dodelete)			/* "do nothing" */
  			return NULL;
  	}
  	else if (resultRelInfo->ri_FdwRoutine)
  	{
  		/*
  		 * delete from foreign table: let the FDW do it
  		 *
  		 * We offer the returning slot as a place to store RETURNING data,
  		 * although the FDW can return some other slot if it wants.
  		 */
  		slot = ExecGetReturningSlot(estate, resultRelInfo);
  		slot = resultRelInfo->ri_FdwRoutine->ExecForeignDelete(estate,
  															   resultRelInfo,
  															   slot,
  															   planSlot);
  
  		if (slot == NULL)		/* "do nothing" */
  			return NULL;
  
  		/*
  		 * RETURNING expressions might reference the tableoid column, so
  		 * (re)initialize tts_tableOid before evaluating them.
  		 */
  		if (TTS_EMPTY(slot))
  			ExecStoreAllNullTuple(slot);
  
  		slot->tts_tableOid = RelationGetRelid(resultRelationDesc);
  	}
  	else
  	{
  		/*
  		 * delete the tuple
  		 *
  		 * Note: if es_crosscheck_snapshot isn't InvalidSnapshot, we check
  		 * that the row to be deleted is visible to that snapshot, and throw a
  		 * can't-serialize error if not. This is a special-case behavior
  		 * needed for referential integrity updates in transaction-snapshot
  		 * mode transactions.
  		 */
  ldelete:;
  		result = table_tuple_delete(resultRelationDesc, tupleid,
  									estate->es_output_cid,
  									estate->es_snapshot,
  									estate->es_crosscheck_snapshot,
  									true /* wait for commit */ ,
  									&tmfd,
  									changingPart);
  
  		switch (result)
  		{
  			case TM_SelfModified:
  
  				/*
  				 * The target tuple was already updated or deleted by the
  				 * current command, or by a later command in the current
  				 * transaction.  The former case is possible in a join DELETE
  				 * where multiple tuples join to the same target tuple. This
  				 * is somewhat questionable, but Postgres has always allowed
  				 * it: we just ignore additional deletion attempts.
  				 *
  				 * The latter case arises if the tuple is modified by a
  				 * command in a BEFORE trigger, or perhaps by a command in a
  				 * volatile function used in the query.  In such situations we
  				 * should not ignore the deletion, but it is equally unsafe to
  				 * proceed.  We don't want to discard the original DELETE
  				 * while keeping the triggered actions based on its deletion;
  				 * and it would be no better to allow the original DELETE
  				 * while discarding updates that it triggered.  The row update
  				 * carries some information that might be important according
  				 * to business rules; so throwing an error is the only safe
  				 * course.
  				 *
  				 * If a trigger actually intends this type of interaction, it
  				 * can re-execute the DELETE and then return NULL to cancel
  				 * the outer delete.
  				 */
  				if (tmfd.cmax != estate->es_output_cid)
  					ereport(ERROR,
  							(errcode(ERRCODE_TRIGGERED_DATA_CHANGE_VIOLATION),
  							 errmsg("tuple to be deleted was already modified by an operation triggered by the current command"),
  							 errhint("Consider using an AFTER trigger instead of a BEFORE trigger to propagate changes to other rows.")));
  
  				/* Else, already deleted by self; nothing to do */
  				return NULL;
  
  			case TM_Ok:
  				break;
  
  			case TM_Updated:
  				{
  					TupleTableSlot *inputslot;
  					TupleTableSlot *epqslot;
  
  					if (IsolationUsesXactSnapshot())
  						ereport(ERROR,
  								(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
  								 errmsg("could not serialize access due to concurrent update")));
  
  					/*
  					 * Already know that we're going to need to do EPQ, so
  					 * fetch tuple directly into the right slot.
  					 */
  					EvalPlanQualBegin(epqstate);
  					inputslot = EvalPlanQualSlot(epqstate, resultRelationDesc,
  												 resultRelInfo->ri_RangeTableIndex);
  
  					result = table_tuple_lock(resultRelationDesc, tupleid,
  											  estate->es_snapshot,
  											  inputslot, estate->es_output_cid,
  											  LockTupleExclusive, LockWaitBlock,
  											  TUPLE_LOCK_FLAG_FIND_LAST_VERSION,
  											  &tmfd);
  
  					switch (result)
  					{
  						case TM_Ok:
  							Assert(tmfd.traversed);
  							epqslot = EvalPlanQual(epqstate,
  												   resultRelationDesc,
  												   resultRelInfo->ri_RangeTableIndex,
  												   inputslot);
  							if (TupIsNull(epqslot))
  								/* Tuple not passing quals anymore, exiting... */
  								return NULL;
  
  							/*
  							 * If requested, skip delete and pass back the
  							 * updated row.
  							 */
  							if (epqreturnslot)
  							{
  								*epqreturnslot = epqslot;
  								return NULL;
  							}
  							else
  								goto ldelete;
  
  						case TM_SelfModified:
  
  							/*
  							 * This can be reached when following an update
  							 * chain from a tuple updated by another session,
  							 * reaching a tuple that was already updated in
  							 * this transaction. If previously updated by this
  							 * command, ignore the delete, otherwise error
  							 * out.
  							 *
  							 * See also TM_SelfModified response to
  							 * table_tuple_delete() above.
  							 */
  							if (tmfd.cmax != estate->es_output_cid)
  								ereport(ERROR,
  										(errcode(ERRCODE_TRIGGERED_DATA_CHANGE_VIOLATION),
  										 errmsg("tuple to be deleted was already modified by an operation triggered by the current command"),
  										 errhint("Consider using an AFTER trigger instead of a BEFORE trigger to propagate changes to other rows.")));
  							return NULL;
  
  						case TM_Deleted:
  							/* tuple already deleted; nothing to do */
  							return NULL;
  
  						default:
  
  							/*
  							 * TM_Invisible should be impossible because we're
  							 * waiting for updated row versions, and would
  							 * already have errored out if the first version
  							 * is invisible.
  							 *
  							 * TM_Updated should be impossible, because we're
  							 * locking the latest version via
  							 * TUPLE_LOCK_FLAG_FIND_LAST_VERSION.
  							 */
  							elog(ERROR, "unexpected table_tuple_lock status: %u",
  								 result);
  							return NULL;
  					}
  
  					Assert(false);
  					break;
  				}
  
  			case TM_Deleted:
  				if (IsolationUsesXactSnapshot())
  					ereport(ERROR,
  							(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
  							 errmsg("could not serialize access due to concurrent delete")));
  				/* tuple already deleted; nothing to do */
  				return NULL;
  
  			default:
  				elog(ERROR, "unrecognized table_tuple_delete status: %u",
  					 result);
  				return NULL;
  		}
  
  		/*
  		 * Note: Normally one would think that we have to delete index tuples
  		 * associated with the heap tuple now...
  		 *
  		 * ... but in POSTGRES, we have no need to do this because VACUUM will
  		 * take care of it later.  We can't delete index tuples immediately
  		 * anyway, since the tuple is still visible to other transactions.
  		 */
  	}
  
  	if (canSetTag)
  		(estate->es_processed)++;
  
  	/* Tell caller that the delete actually happened. */
  	if (tupleDeleted)
  		*tupleDeleted = true;
  
  	/*
  	 * If this delete is the result of a partition key update that moved the
  	 * tuple to a new partition, put this row into the transition OLD TABLE,
  	 * if there is one. We need to do this separately for DELETE and INSERT
  	 * because they happen on different tables.
  	 */
  	ar_delete_trig_tcs = mtstate->mt_transition_capture;
  	if (mtstate->operation == CMD_UPDATE && mtstate->mt_transition_capture
  		&& mtstate->mt_transition_capture->tcs_update_old_table)
  	{
  		ExecARUpdateTriggers(estate, resultRelInfo,
  							 tupleid,
  							 oldtuple,
  							 NULL,
  							 NULL,
  							 mtstate->mt_transition_capture);
  
  		/*
  		 * We've already captured the NEW TABLE row, so make sure any AR
  		 * DELETE trigger fired below doesn't capture it again.
  		 */
  		ar_delete_trig_tcs = NULL;
  	}
  
  	/* AFTER ROW DELETE Triggers */
  	ExecARDeleteTriggers(estate, resultRelInfo, tupleid, oldtuple,
  						 ar_delete_trig_tcs);
  
  	/* Process RETURNING if present and if requested */
  	if (processReturning && resultRelInfo->ri_projectReturning && sql_dialect != SQL_DIALECT_TSQL)
  	{
  		/*
  		 * We have to put the target tuple into a slot, which means first we
  		 * gotta fetch it.  We can use the trigger tuple slot.
  		 */
  		TupleTableSlot *rslot;
  
  		if (resultRelInfo->ri_FdwRoutine)
  		{
  			/* FDW must have provided a slot containing the deleted row */
  			Assert(!TupIsNull(slot));
  		}
  		else
  		{
  			slot = ExecGetReturningSlot(estate, resultRelInfo);
  			if (oldtuple != NULL)
  			{
  				ExecForceStoreHeapTuple(oldtuple, slot, false);
  			}
  			else
  			{
  				if (!table_tuple_fetch_row_version(resultRelationDesc, tupleid,
  												   SnapshotAny, slot))
  					elog(ERROR, "failed to fetch deleted tuple for DELETE RETURNING");
  			}
  		}
  
  		rslot = ExecProcessReturning(resultRelInfo, slot, planSlot);
  
  		/*
  		 * Before releasing the target tuple again, make sure rslot has a
  		 * local copy of any pass-by-reference values.
  		 */
  		ExecMaterializeSlot(rslot);
  
  		ExecClearTuple(slot);
  
  		return rslot;
  	}
  
  	if (processReturning && resultRelInfo->ri_projectReturning && rslot_output)
  		return rslot_output;
  
  	return NULL;
  }
  
  /*
   * ExecCrossPartitionUpdate --- Move an updated tuple to another partition.
   *
   * This works by first deleting the old tuple from the current partition,
   * followed by inserting the new tuple into the root parent table, that is,
   * mtstate->rootResultRelInfo.  It will be re-routed from there to the
   * correct partition.
   *
   * Returns true if the tuple has been successfully moved, or if it's found
   * that the tuple was concurrently deleted so there's nothing more to do
   * for the caller.
   *
   * False is returned if the tuple we're trying to move is found to have been
   * concurrently updated.  In that case, the caller must to check if the
   * updated tuple that's returned in *retry_slot still needs to be re-routed,
   * and call this function again or perform a regular update accordingly.
   */
  static bool
  ExecCrossPartitionUpdate(ModifyTableState *mtstate,
  						 ResultRelInfo *resultRelInfo,
  						 ItemPointer tupleid, HeapTuple oldtuple,
  						 TupleTableSlot *slot, TupleTableSlot *planSlot,
  						 EPQState *epqstate, bool canSetTag,
  						 TupleTableSlot **retry_slot,
  						 TupleTableSlot **inserted_tuple)
  {
  	EState	   *estate = mtstate->ps.state;
  	TupleConversionMap *tupconv_map;
  	bool		tuple_deleted;
  	TupleTableSlot *epqslot = NULL;
  
  	*inserted_tuple = NULL;
  	*retry_slot = NULL;
  
  	/*
  	 * Disallow an INSERT ON CONFLICT DO UPDATE that causes the original row
  	 * to migrate to a different partition.  Maybe this can be implemented
  	 * some day, but it seems a fringe feature with little redeeming value.
  	 */
  	if (((ModifyTable *) mtstate->ps.plan)->onConflictAction == ONCONFLICT_UPDATE)
  		ereport(ERROR,
  				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
  				 errmsg("invalid ON UPDATE specification"),
  				 errdetail("The result tuple would appear in a different partition than the original tuple.")));
  
  	/*
  	 * When an UPDATE is run directly on a leaf partition, simply fail with a
  	 * partition constraint violation error.
  	 */
  	if (resultRelInfo == mtstate->rootResultRelInfo)
  		ExecPartitionCheckEmitError(resultRelInfo, slot, estate);
  
  	/* Initialize tuple routing info if not already done. */
  	if (mtstate->mt_partition_tuple_routing == NULL)
  	{
  		Relation	rootRel = mtstate->rootResultRelInfo->ri_RelationDesc;
  		MemoryContext oldcxt;
  
  		/* Things built here have to last for the query duration. */
  		oldcxt = MemoryContextSwitchTo(estate->es_query_cxt);
  
  		mtstate->mt_partition_tuple_routing =
  			ExecSetupPartitionTupleRouting(estate, rootRel);
  
  		/*
  		 * Before a partition's tuple can be re-routed, it must first be
  		 * converted to the root's format, so we'll need a slot for storing
  		 * such tuples.
  		 */
  		Assert(mtstate->mt_root_tuple_slot == NULL);
  		mtstate->mt_root_tuple_slot = table_slot_create(rootRel, NULL);
  
  		MemoryContextSwitchTo(oldcxt);
  	}
  
  	/*
  	 * Row movement, part 1.  Delete the tuple, but skip RETURNING processing.
  	 * We want to return rows from INSERT.
  	 */
  	ExecDelete(mtstate, resultRelInfo, tupleid, oldtuple, planSlot,
  			   epqstate, estate,
  			   false,			/* processReturning */
  			   false,			/* canSetTag */
  			   true,			/* changingPart */
  			   &tuple_deleted, &epqslot);
  
  	/*
  	 * For some reason if DELETE didn't happen (e.g. trigger prevented it, or
  	 * it was already deleted by self, or it was concurrently deleted by
  	 * another transaction), then we should skip the insert as well;
  	 * otherwise, an UPDATE could cause an increase in the total number of
  	 * rows across all partitions, which is clearly wrong.
  	 *
  	 * For a normal UPDATE, the case where the tuple has been the subject of a
  	 * concurrent UPDATE or DELETE would be handled by the EvalPlanQual
  	 * machinery, but for an UPDATE that we've translated into a DELETE from
  	 * this partition and an INSERT into some other partition, that's not
  	 * available, because CTID chains can't span relation boundaries.  We
  	 * mimic the semantics to a limited extent by skipping the INSERT if the
  	 * DELETE fails to find a tuple.  This ensures that two concurrent
  	 * attempts to UPDATE the same tuple at the same time can't turn one tuple
  	 * into two, and that an UPDATE of a just-deleted tuple can't resurrect
  	 * it.
  	 */
  	if (!tuple_deleted)
  	{
  		/*
  		 * epqslot will be typically NULL.  But when ExecDelete() finds that
  		 * another transaction has concurrently updated the same row, it
  		 * re-fetches the row, skips the delete, and epqslot is set to the
  		 * re-fetched tuple slot.  In that case, we need to do all the checks
  		 * again.
  		 */
  		if (TupIsNull(epqslot))
  			return true;
  		else
  		{
  			/* Fetch the most recent version of old tuple. */
  			TupleTableSlot *oldSlot;
  
  			/* ... but first, make sure ri_oldTupleSlot is initialized. */
  			if (unlikely(!resultRelInfo->ri_projectNewInfoValid))
  				ExecInitUpdateProjection(mtstate, resultRelInfo);
  			oldSlot = resultRelInfo->ri_oldTupleSlot;
  			if (!table_tuple_fetch_row_version(resultRelInfo->ri_RelationDesc,
  											   tupleid,
  											   SnapshotAny,
  											   oldSlot))
  				elog(ERROR, "failed to fetch tuple being updated");
  			*retry_slot = ExecGetUpdateNewTuple(resultRelInfo, epqslot,
  												oldSlot);
  			return false;
  		}
  	}
  
  	/*
  	 * resultRelInfo is one of the per-relation resultRelInfos.  So we should
  	 * convert the tuple into root's tuple descriptor if needed, since
  	 * ExecInsert() starts the search from root.
  	 */
  	tupconv_map = ExecGetChildToRootMap(resultRelInfo);
  	if (tupconv_map != NULL)
  		slot = execute_attr_map_slot(tupconv_map->attrMap,
  									 slot,
  									 mtstate->mt_root_tuple_slot);
  
  	/* Tuple routing starts from the root table. */
  	*inserted_tuple = ExecInsert(mtstate, mtstate->rootResultRelInfo, slot,
  								 planSlot, estate, canSetTag);
  
  	/*
  	 * Reset the transition state that may possibly have been written by
  	 * INSERT.
  	 */
  	if (mtstate->mt_transition_capture)
  		mtstate->mt_transition_capture->tcs_original_insert_tuple = NULL;
  
  	/* We're done moving. */
  	return true;
  }
  
  /* ----------------------------------------------------------------
   *		ExecUpdate
   *
   *		note: we can't run UPDATE queries with transactions
   *		off because UPDATEs are actually INSERTs and our
   *		scan will mistakenly loop forever, updating the tuple
   *		it just inserted..  This should be fixed but until it
   *		is, we don't want to get stuck in an infinite loop
   *		which corrupts your database..
   *
   *		When updating a table, tupleid identifies the tuple to
   *		update and oldtuple is NULL.  When updating a view, oldtuple
   *		is passed to the INSTEAD OF triggers and identifies what to
   *		update, and tupleid is invalid.  When updating a foreign table,
   *		tupleid is invalid; the FDW has to figure out which row to
   *		update using data from the planSlot.  oldtuple is passed to
   *		foreign table triggers; it is NULL when the foreign table has
   *		no relevant triggers.
   *
   *		slot contains the new tuple value to be stored.
   *		planSlot is the output of the ModifyTable's subplan; we use it
   *		to access values from other input tables (for RETURNING),
   *		row-ID junk columns, etc.
   *
   *		Returns RETURNING result if any, otherwise NULL.
   * ----------------------------------------------------------------
   */
  static TupleTableSlot *
  ExecUpdate(ModifyTableState *mtstate,
  		   ResultRelInfo *resultRelInfo,
  		   ItemPointer tupleid,
  		   HeapTuple oldtuple,
  		   TupleTableSlot *slot,
  		   TupleTableSlot *planSlot,
  		   EPQState *epqstate,
  		   EState *estate,
  		   bool canSetTag)
  {
  	Relation	resultRelationDesc = resultRelInfo->ri_RelationDesc;
  	TM_Result	result;
  	TM_FailureData tmfd;
  	List	   *recheckIndexes = NIL;
  	TupleTableSlot *rslot = NULL;
  
  	/*
  	 * abort the operation if not running transactions
  	 */
  	if (IsBootstrapProcessingMode())
  		elog(ERROR, "cannot UPDATE during bootstrap");
  
  	ExecMaterializeSlot(slot);
  
  	/*
  	 * Open the table's indexes, if we have not done so already, so that we
  	 * can add new index entries for the updated tuple.
  	 */
  	if (resultRelationDesc->rd_rel->relhasindex &&
  		resultRelInfo->ri_IndexRelationDescs == NULL)
  		ExecOpenIndices(resultRelInfo, false);
  
  	/* BEFORE ROW UPDATE Triggers */
  	if (resultRelInfo->ri_TrigDesc &&
  		resultRelInfo->ri_TrigDesc->trig_update_before_row)
  	{
  		if (!ExecBRUpdateTriggers(estate, epqstate, resultRelInfo,
  								  tupleid, oldtuple, slot))
  			return NULL;		/* "do nothing" */
  	}
  
  	/* Process RETURNING if present */
  	if (resultRelInfo->ri_projectReturning && sql_dialect == SQL_DIALECT_TSQL)
  		rslot = ExecProcessReturning(resultRelInfo, slot, planSlot);
  
  	if (resultRelInfo->ri_TrigDesc &&
  		resultRelInfo->ri_TrigDesc->trig_update_instead_statement &&
  		sql_dialect == SQL_DIALECT_TSQL && 
  		isTsqlInsteadofTriggerExecution(estate, resultRelInfo, TRIGGER_EVENT_INSTEAD))
  	{
  		ExecIRUpdateTriggersTSQL(estate, resultRelInfo, tupleid, oldtuple, slot, recheckIndexes, mtstate->mt_transition_capture);
  		return NULL;
  	}
  
  	/* INSTEAD OF ROW UPDATE Triggers */
  	if (resultRelInfo->ri_TrigDesc &&
  		resultRelInfo->ri_TrigDesc->trig_update_instead_row)
  	{
  		if (!ExecIRUpdateTriggers(estate, resultRelInfo,
  								  oldtuple, slot))
  			return NULL;		/* "do nothing" */
  	}
  	else if (resultRelInfo->ri_FdwRoutine)
  	{
  		/*
  		 * GENERATED expressions might reference the tableoid column, so
  		 * (re-)initialize tts_tableOid before evaluating them.
  		 */
  		slot->tts_tableOid = RelationGetRelid(resultRelInfo->ri_RelationDesc);
  
  		/*
  		 * Compute stored generated columns
  		 */
  		if (resultRelationDesc->rd_att->constr &&
  			resultRelationDesc->rd_att->constr->has_generated_stored)
  			ExecComputeStoredGenerated(resultRelInfo, estate, slot,
  									   CMD_UPDATE);
  
  		/*
  		 * update in foreign table: let the FDW do it
  		 */
  		slot = resultRelInfo->ri_FdwRoutine->ExecForeignUpdate(estate,
  															   resultRelInfo,
  															   slot,
  															   planSlot);
  
  		if (slot == NULL)		/* "do nothing" */
  			return NULL;
  
  		/*
  		 * AFTER ROW Triggers or RETURNING expressions might reference the
  		 * tableoid column, so (re-)initialize tts_tableOid before evaluating
  		 * them.  (This covers the case where the FDW replaced the slot.)
  		 */
  		slot->tts_tableOid = RelationGetRelid(resultRelationDesc);
  	}
  	else
  	{
  		LockTupleMode lockmode;
  		bool		partition_constraint_failed;
  		bool		update_indexes;
  
  		/*
  		 * Constraints and GENERATED expressions might reference the tableoid
  		 * column, so (re-)initialize tts_tableOid before evaluating them.
  		 */
  		slot->tts_tableOid = RelationGetRelid(resultRelationDesc);
  
  		/*
  		 * Compute stored generated columns
  		 */
  		if (resultRelationDesc->rd_att->constr &&
  			resultRelationDesc->rd_att->constr->has_generated_stored)
  			ExecComputeStoredGenerated(resultRelInfo, estate, slot,
  									   CMD_UPDATE);
  
  		/*
  		 * Check any RLS UPDATE WITH CHECK policies
  		 *
  		 * If we generate a new candidate tuple after EvalPlanQual testing, we
  		 * must loop back here and recheck any RLS policies and constraints.
  		 * (We don't need to redo triggers, however.  If there are any BEFORE
  		 * triggers then trigger.c will have done table_tuple_lock to lock the
  		 * correct tuple, so there's no need to do them again.)
  		 */
  lreplace:;
  
  		/* ensure slot is independent, consider e.g. EPQ */
  		ExecMaterializeSlot(slot);
  
  		/*
  		 * If partition constraint fails, this row might get moved to another
  		 * partition, in which case we should check the RLS CHECK policy just
  		 * before inserting into the new partition, rather than doing it here.
  		 * This is because a trigger on that partition might again change the
  		 * row.  So skip the WCO checks if the partition constraint fails.
  		 */
  		partition_constraint_failed =
  			resultRelationDesc->rd_rel->relispartition &&
  			!ExecPartitionCheck(resultRelInfo, slot, estate, false);
  
  		if (!partition_constraint_failed &&
  			resultRelInfo->ri_WithCheckOptions != NIL)
  		{
  			/*
  			 * ExecWithCheckOptions() will skip any WCOs which are not of the
  			 * kind we are looking for at this point.
  			 */
  			ExecWithCheckOptions(WCO_RLS_UPDATE_CHECK,
  								 resultRelInfo, slot, estate);
  		}
  
  		/*
  		 * If a partition check failed, try to move the row into the right
  		 * partition.
  		 */
  		if (partition_constraint_failed)
  		{
  			TupleTableSlot *inserted_tuple,
  					   *retry_slot;
  			bool		retry;
  
  			/*
  			 * ExecCrossPartitionUpdate will first DELETE the row from the
  			 * partition it's currently in and then insert it back into the
  			 * root table, which will re-route it to the correct partition.
  			 * The first part may have to be repeated if it is detected that
  			 * the tuple we're trying to move has been concurrently updated.
  			 */
  			retry = !ExecCrossPartitionUpdate(mtstate, resultRelInfo, tupleid,
  											  oldtuple, slot, planSlot,
  											  epqstate, canSetTag,
  											  &retry_slot, &inserted_tuple);
  			if (retry)
  			{
  				slot = retry_slot;
  				goto lreplace;
  			}
  
  			return inserted_tuple;
  		}
  
  		/*
  		 * Check the constraints of the tuple.  We've already checked the
  		 * partition constraint above; however, we must still ensure the tuple
  		 * passes all other constraints, so we will call ExecConstraints() and
  		 * have it validate all remaining checks.
  		 */
  		if (resultRelationDesc->rd_att->constr)
  			ExecConstraints(resultRelInfo, slot, estate);
  
  		/*
  		 * replace the heap tuple
  		 *
  		 * Note: if es_crosscheck_snapshot isn't InvalidSnapshot, we check
  		 * that the row to be updated is visible to that snapshot, and throw a
  		 * can't-serialize error if not. This is a special-case behavior
  		 * needed for referential integrity updates in transaction-snapshot
  		 * mode transactions.
  		 */
  		result = table_tuple_update(resultRelationDesc, tupleid, slot,
  									estate->es_output_cid,
  									estate->es_snapshot,
  									estate->es_crosscheck_snapshot,
  									true /* wait for commit */ ,
  									&tmfd, &lockmode, &update_indexes);
  
  		switch (result)
  		{
  			case TM_SelfModified:
  
  				/*
  				 * The target tuple was already updated or deleted by the
  				 * current command, or by a later command in the current
  				 * transaction.  The former case is possible in a join UPDATE
  				 * where multiple tuples join to the same target tuple. This
  				 * is pretty questionable, but Postgres has always allowed it:
  				 * we just execute the first update action and ignore
  				 * additional update attempts.
  				 *
  				 * The latter case arises if the tuple is modified by a
  				 * command in a BEFORE trigger, or perhaps by a command in a
  				 * volatile function used in the query.  In such situations we
  				 * should not ignore the update, but it is equally unsafe to
  				 * proceed.  We don't want to discard the original UPDATE
  				 * while keeping the triggered actions based on it; and we
  				 * have no principled way to merge this update with the
  				 * previous ones.  So throwing an error is the only safe
  				 * course.
  				 *
  				 * If a trigger actually intends this type of interaction, it
  				 * can re-execute the UPDATE (assuming it can figure out how)
  				 * and then return NULL to cancel the outer update.
  				 */
  				if (tmfd.cmax != estate->es_output_cid)
  					ereport(ERROR,
  							(errcode(ERRCODE_TRIGGERED_DATA_CHANGE_VIOLATION),
  							 errmsg("tuple to be updated was already modified by an operation triggered by the current command"),
  							 errhint("Consider using an AFTER trigger instead of a BEFORE trigger to propagate changes to other rows.")));
  
  				/* Else, already updated by self; nothing to do */
  				return NULL;
  
  			case TM_Ok:
  				break;
  
  			case TM_Updated:
  				{
  					TupleTableSlot *inputslot;
  					TupleTableSlot *epqslot;
  					TupleTableSlot *oldSlot;
  
  					if (IsolationUsesXactSnapshot())
  						ereport(ERROR,
  								(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
  								 errmsg("could not serialize access due to concurrent update")));
  
  					/*
  					 * Already know that we're going to need to do EPQ, so
  					 * fetch tuple directly into the right slot.
  					 */
  					inputslot = EvalPlanQualSlot(epqstate, resultRelationDesc,
  												 resultRelInfo->ri_RangeTableIndex);
  
  					result = table_tuple_lock(resultRelationDesc, tupleid,
  											  estate->es_snapshot,
  											  inputslot, estate->es_output_cid,
  											  lockmode, LockWaitBlock,
  											  TUPLE_LOCK_FLAG_FIND_LAST_VERSION,
  											  &tmfd);
  
  					switch (result)
  					{
  						case TM_Ok:
  							Assert(tmfd.traversed);
  
  							epqslot = EvalPlanQual(epqstate,
  												   resultRelationDesc,
  												   resultRelInfo->ri_RangeTableIndex,
  												   inputslot);
  							if (TupIsNull(epqslot))
  								/* Tuple not passing quals anymore, exiting... */
  								return NULL;
  
  							/* Make sure ri_oldTupleSlot is initialized. */
  							if (unlikely(!resultRelInfo->ri_projectNewInfoValid))
  								ExecInitUpdateProjection(mtstate, resultRelInfo);
  
  							/* Fetch the most recent version of old tuple. */
  							oldSlot = resultRelInfo->ri_oldTupleSlot;
  							if (!table_tuple_fetch_row_version(resultRelationDesc,
  															   tupleid,
  															   SnapshotAny,
  															   oldSlot))
  								elog(ERROR, "failed to fetch tuple being updated");
  							slot = ExecGetUpdateNewTuple(resultRelInfo,
  														 epqslot, oldSlot);
  							goto lreplace;
  
  						case TM_Deleted:
  							/* tuple already deleted; nothing to do */
  							return NULL;
  
  						case TM_SelfModified:
  
  							/*
  							 * This can be reached when following an update
  							 * chain from a tuple updated by another session,
  							 * reaching a tuple that was already updated in
  							 * this transaction. If previously modified by
  							 * this command, ignore the redundant update,
  							 * otherwise error out.
  							 *
  							 * See also TM_SelfModified response to
  							 * table_tuple_update() above.
  							 */
  							if (tmfd.cmax != estate->es_output_cid)
  								ereport(ERROR,
  										(errcode(ERRCODE_TRIGGERED_DATA_CHANGE_VIOLATION),
  										 errmsg("tuple to be updated was already modified by an operation triggered by the current command"),
  										 errhint("Consider using an AFTER trigger instead of a BEFORE trigger to propagate changes to other rows.")));
  							return NULL;
  
  						default:
  							/* see table_tuple_lock call in ExecDelete() */
  							elog(ERROR, "unexpected table_tuple_lock status: %u",
  								 result);
  							return NULL;
  					}
  				}
  
  				break;
  
  			case TM_Deleted:
  				if (IsolationUsesXactSnapshot())
  					ereport(ERROR,
  							(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
  							 errmsg("could not serialize access due to concurrent delete")));
  				/* tuple already deleted; nothing to do */
  				return NULL;
  
  			default:
  				elog(ERROR, "unrecognized table_tuple_update status: %u",
  					 result);
  				return NULL;
  		}
  
  		/* insert index entries for tuple if necessary */
  		if (resultRelInfo->ri_NumIndices > 0 && update_indexes)
  			recheckIndexes = ExecInsertIndexTuples(resultRelInfo,
  												   slot, estate, true, false,
  												   NULL, NIL);
  	}
  
  	if (canSetTag)
  		(estate->es_processed)++;
  
  	/* AFTER ROW UPDATE Triggers */
  	ExecARUpdateTriggers(estate, resultRelInfo, tupleid, oldtuple, slot,
  						 recheckIndexes,
  						 mtstate->operation == CMD_INSERT ?
  						 mtstate->mt_oc_transition_capture :
  						 mtstate->mt_transition_capture);
  
  	list_free(recheckIndexes);
  
  	/*
  	 * Check any WITH CHECK OPTION constraints from parent views.  We are
  	 * required to do this after testing all constraints and uniqueness
  	 * violations per the SQL spec, so we do it after actually updating the
  	 * record in the heap and all indexes.
  	 *
  	 * ExecWithCheckOptions() will skip any WCOs which are not of the kind we
  	 * are looking for at this point.
  	 */
  	if (resultRelInfo->ri_WithCheckOptions != NIL)
  		ExecWithCheckOptions(WCO_VIEW_CHECK, resultRelInfo, slot, estate);
  
  	/* Process RETURNING if present */
  	if (resultRelInfo->ri_projectReturning && sql_dialect != SQL_DIALECT_TSQL)
  		return ExecProcessReturning(resultRelInfo, slot, planSlot);
  
  	if (resultRelInfo->ri_projectReturning)
  		return rslot;
  
  	return NULL;
  }
  
  /*
   * ExecOnConflictUpdate --- execute UPDATE of INSERT ON CONFLICT DO UPDATE
   *
   * Try to lock tuple for update as part of speculative insertion.  If
   * a qual originating from ON CONFLICT DO UPDATE is satisfied, update
   * (but still lock row, even though it may not satisfy estate's
   * snapshot).
   *
   * Returns true if we're done (with or without an update), or false if
   * the caller must retry the INSERT from scratch.
   */
  static bool
  ExecOnConflictUpdate(ModifyTableState *mtstate,
  					 ResultRelInfo *resultRelInfo,
  					 ItemPointer conflictTid,
  					 TupleTableSlot *planSlot,
  					 TupleTableSlot *excludedSlot,
  					 EState *estate,
  					 bool canSetTag,
  					 TupleTableSlot **returning)
  {
  	ExprContext *econtext = mtstate->ps.ps_ExprContext;
  	Relation	relation = resultRelInfo->ri_RelationDesc;
  	ExprState  *onConflictSetWhere = resultRelInfo->ri_onConflict->oc_WhereClause;
  	TupleTableSlot *existing = resultRelInfo->ri_onConflict->oc_Existing;
  	TM_FailureData tmfd;
  	LockTupleMode lockmode;
  	TM_Result	test;
  	Datum		xminDatum;
  	TransactionId xmin;
  	bool		isnull;
  
  	/* Determine lock mode to use */
  	lockmode = ExecUpdateLockMode(estate, resultRelInfo);
  
  	/*
  	 * Lock tuple for update.  Don't follow updates when tuple cannot be
  	 * locked without doing so.  A row locking conflict here means our
  	 * previous conclusion that the tuple is conclusively committed is not
  	 * true anymore.
  	 */
  	test = table_tuple_lock(relation, conflictTid,
  							estate->es_snapshot,
  							existing, estate->es_output_cid,
  							lockmode, LockWaitBlock, 0,
  							&tmfd);
  	switch (test)
  	{
  		case TM_Ok:
  			/* success! */
  			break;
  
  		case TM_Invisible:
  
  			/*
  			 * This can occur when a just inserted tuple is updated again in
  			 * the same command. E.g. because multiple rows with the same
  			 * conflicting key values are inserted.
  			 *
  			 * This is somewhat similar to the ExecUpdate() TM_SelfModified
  			 * case.  We do not want to proceed because it would lead to the
  			 * same row being updated a second time in some unspecified order,
  			 * and in contrast to plain UPDATEs there's no historical behavior
  			 * to break.
  			 *
  			 * It is the user's responsibility to prevent this situation from
  			 * occurring.  These problems are why SQL-2003 similarly specifies
  			 * that for SQL MERGE, an exception must be raised in the event of
  			 * an attempt to update the same row twice.
  			 */
  			xminDatum = slot_getsysattr(existing,
  										MinTransactionIdAttributeNumber,
  										&isnull);
  			Assert(!isnull);
  			xmin = DatumGetTransactionId(xminDatum);
  
  			if (TransactionIdIsCurrentTransactionId(xmin))
  				ereport(ERROR,
  						(errcode(ERRCODE_CARDINALITY_VIOLATION),
  						 errmsg("ON CONFLICT DO UPDATE command cannot affect row a second time"),
  						 errhint("Ensure that no rows proposed for insertion within the same command have duplicate constrained values.")));
  
  			/* This shouldn't happen */
  			elog(ERROR, "attempted to lock invisible tuple");
  			break;
  
  		case TM_SelfModified:
  
  			/*
  			 * This state should never be reached. As a dirty snapshot is used
  			 * to find conflicting tuples, speculative insertion wouldn't have
  			 * seen this row to conflict with.
  			 */
  			elog(ERROR, "unexpected self-updated tuple");
  			break;
  
  		case TM_Updated:
  			if (IsolationUsesXactSnapshot())
  				ereport(ERROR,
  						(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
  						 errmsg("could not serialize access due to concurrent update")));
  
  			/*
  			 * As long as we don't support an UPDATE of INSERT ON CONFLICT for
  			 * a partitioned table we shouldn't reach to a case where tuple to
  			 * be lock is moved to another partition due to concurrent update
  			 * of the partition key.
  			 */
  			Assert(!ItemPointerIndicatesMovedPartitions(&tmfd.ctid));
  
  			/*
  			 * Tell caller to try again from the very start.
  			 *
  			 * It does not make sense to use the usual EvalPlanQual() style
  			 * loop here, as the new version of the row might not conflict
  			 * anymore, or the conflicting tuple has actually been deleted.
  			 */
  			ExecClearTuple(existing);
  			return false;
  
  		case TM_Deleted:
  			if (IsolationUsesXactSnapshot())
  				ereport(ERROR,
  						(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
  						 errmsg("could not serialize access due to concurrent delete")));
  
  			/* see TM_Updated case */
  			Assert(!ItemPointerIndicatesMovedPartitions(&tmfd.ctid));
  			ExecClearTuple(existing);
  			return false;
  
  		default:
  			elog(ERROR, "unrecognized table_tuple_lock status: %u", test);
  	}
  
  	/* Success, the tuple is locked. */
  
  	/*
  	 * Verify that the tuple is visible to our MVCC snapshot if the current
  	 * isolation level mandates that.
  	 *
  	 * It's not sufficient to rely on the check within ExecUpdate() as e.g.
  	 * CONFLICT ... WHERE clause may prevent us from reaching that.
  	 *
  	 * This means we only ever continue when a new command in the current
  	 * transaction could see the row, even though in READ COMMITTED mode the
  	 * tuple will not be visible according to the current statement's
  	 * snapshot.  This is in line with the way UPDATE deals with newer tuple
  	 * versions.
  	 */
  	ExecCheckTupleVisible(estate, relation, existing);
  
  	/*
  	 * Make tuple and any needed join variables available to ExecQual and
  	 * ExecProject.  The EXCLUDED tuple is installed in ecxt_innertuple, while
  	 * the target's existing tuple is installed in the scantuple.  EXCLUDED
  	 * has been made to reference INNER_VAR in setrefs.c, but there is no
  	 * other redirection.
  	 */
  	econtext->ecxt_scantuple = existing;
  	econtext->ecxt_innertuple = excludedSlot;
  	econtext->ecxt_outertuple = NULL;
  
  	if (!ExecQual(onConflictSetWhere, econtext))
  	{
  		ExecClearTuple(existing);	/* see return below */
  		InstrCountFiltered1(&mtstate->ps, 1);
  		return true;			/* done with the tuple */
  	}
  
  	if (resultRelInfo->ri_WithCheckOptions != NIL)
  	{
  		/*
  		 * Check target's existing tuple against UPDATE-applicable USING
  		 * security barrier quals (if any), enforced here as RLS checks/WCOs.
  		 *
  		 * The rewriter creates UPDATE RLS checks/WCOs for UPDATE security
  		 * quals, and stores them as WCOs of "kind" WCO_RLS_CONFLICT_CHECK,
  		 * but that's almost the extent of its special handling for ON
  		 * CONFLICT DO UPDATE.
  		 *
  		 * The rewriter will also have associated UPDATE applicable straight
  		 * RLS checks/WCOs for the benefit of the ExecUpdate() call that
  		 * follows.  INSERTs and UPDATEs naturally have mutually exclusive WCO
  		 * kinds, so there is no danger of spurious over-enforcement in the
  		 * INSERT or UPDATE path.
  		 */
  		ExecWithCheckOptions(WCO_RLS_CONFLICT_CHECK, resultRelInfo,
  							 existing,
  							 mtstate->ps.state);
  	}
  
  	/* Project the new tuple version */
  	ExecProject(resultRelInfo->ri_onConflict->oc_ProjInfo);
  
  	/*
  	 * Note that it is possible that the target tuple has been modified in
  	 * this session, after the above table_tuple_lock. We choose to not error
  	 * out in that case, in line with ExecUpdate's treatment of similar cases.
  	 * This can happen if an UPDATE is triggered from within ExecQual(),
  	 * ExecWithCheckOptions() or ExecProject() above, e.g. by selecting from a
  	 * wCTE in the ON CONFLICT's SET.
  	 */
  
  	/* Execute UPDATE with projection */
  	*returning = ExecUpdate(mtstate, resultRelInfo, conflictTid, NULL,
  							resultRelInfo->ri_onConflict->oc_ProjSlot,
  							planSlot,
  							&mtstate->mt_epqstate, mtstate->ps.state,
  							canSetTag);
  
  	/*
  	 * Clear out existing tuple, as there might not be another conflict among
  	 * the next input rows. Don't want to hold resources till the end of the
  	 * query.
  	 */
  	ExecClearTuple(existing);
  	return true;
  }
  
  
  /*
   * Process BEFORE EACH STATEMENT triggers
   */
  static void
  fireBSTriggers(ModifyTableState *node)
  {
  	ModifyTable *plan = (ModifyTable *) node->ps.plan;
  	ResultRelInfo *resultRelInfo = node->rootResultRelInfo;
  
  	switch (node->operation)
  	{
  		case CMD_INSERT:
  			ExecBSInsertTriggers(node->ps.state, resultRelInfo);
  			if (plan->onConflictAction == ONCONFLICT_UPDATE)
  				ExecBSUpdateTriggers(node->ps.state,
  									 resultRelInfo);
  			break;
  		case CMD_UPDATE:
  			ExecBSUpdateTriggers(node->ps.state, resultRelInfo);
  			break;
  		case CMD_DELETE:
  			ExecBSDeleteTriggers(node->ps.state, resultRelInfo);
  			break;
  		default:
  			elog(ERROR, "unknown operation");
  			break;
  	}
  }
  
  /*
   * Process INSTEAD OF EACH STATEMENT triggers
   */
  static IOTState
  fireISTriggers(ModifyTableState *node)
  {
  	ModifyTable *plan = (ModifyTable *) node->ps.plan;
  	ResultRelInfo *resultRelInfo = node->resultRelInfo;
  	IOTState ret =IOT_UNKNOWN;
  
  	/*
  	 * If the node modifies a partitioned table, we must fire its triggers.
  	 * Note that in that case, node->resultRelInfo points to the first leaf
  	 * partition, not the root table.
  	 */
  	if (node->rootResultRelInfo != NULL)
  		resultRelInfo = node->rootResultRelInfo;
  
  	switch (node->operation)
  	{
  		case CMD_INSERT:
  			ret = ExecISInsertTriggers(node->ps.state, resultRelInfo, node->mt_transition_capture);
  			if (plan->onConflictAction == ONCONFLICT_UPDATE)
  				ret = ExecISUpdateTriggers(node->ps.state,
  									 resultRelInfo, node->mt_transition_capture);
  			break;
  		case CMD_UPDATE:
  			ret = ExecISUpdateTriggers(node->ps.state, resultRelInfo, node->mt_transition_capture);
  			break;
  		case CMD_DELETE:
  			ret = ExecISDeleteTriggers(node->ps.state, resultRelInfo, node->mt_transition_capture);
  			break;
  		default:
  			elog(ERROR, "unknown operation");
  			break;
  	}
  	return ret;
  }
  
  /*
   * Process AFTER EACH STATEMENT triggers
   */
  static void
  fireASTriggers(ModifyTableState *node)
  {
  	ModifyTable *plan = (ModifyTable *) node->ps.plan;
  	ResultRelInfo *resultRelInfo = node->rootResultRelInfo;
  
  	switch (node->operation)
  	{
  		case CMD_INSERT:
  			if (plan->onConflictAction == ONCONFLICT_UPDATE)
  				ExecASUpdateTriggers(node->ps.state,
  									 resultRelInfo,
  									 node->mt_oc_transition_capture);
  			ExecASInsertTriggers(node->ps.state, resultRelInfo,
  								 node->mt_transition_capture);
  			break;
  		case CMD_UPDATE:
  			ExecASUpdateTriggers(node->ps.state, resultRelInfo,
  								 node->mt_transition_capture);
  			break;
  		case CMD_DELETE:
  			ExecASDeleteTriggers(node->ps.state, resultRelInfo,
  								 node->mt_transition_capture);
  			break;
  		default:
  			elog(ERROR, "unknown operation");
  			break;
  	}
  }
  
  /*
   * Set up the state needed for collecting transition tuples for AFTER
   * triggers.
   */
  static void
  ExecSetupTransitionCaptureState(ModifyTableState *mtstate, EState *estate)
  {
  	ModifyTable *plan = (ModifyTable *) mtstate->ps.plan;
  	ResultRelInfo *targetRelInfo = mtstate->rootResultRelInfo;
  
  	/* Check for transition tables on the directly targeted relation. */
  	mtstate->mt_transition_capture =
  		MakeTransitionCaptureState(targetRelInfo->ri_TrigDesc,
  								   RelationGetRelid(targetRelInfo->ri_RelationDesc),
  								   mtstate->operation);
  	if (plan->operation == CMD_INSERT &&
  		plan->onConflictAction == ONCONFLICT_UPDATE)
  		mtstate->mt_oc_transition_capture =
  			MakeTransitionCaptureState(targetRelInfo->ri_TrigDesc,
  									   RelationGetRelid(targetRelInfo->ri_RelationDesc),
  									   CMD_UPDATE);
  }
  
  /*
   * ExecPrepareTupleRouting --- prepare for routing one tuple
   *
   * Determine the partition in which the tuple in slot is to be inserted,
   * and return its ResultRelInfo in *partRelInfo.  The return value is
   * a slot holding the tuple of the partition rowtype.
   *
   * This also sets the transition table information in mtstate based on the
   * selected partition.
   */
  static TupleTableSlot *
  ExecPrepareTupleRouting(ModifyTableState *mtstate,
  						EState *estate,
  						PartitionTupleRouting *proute,
  						ResultRelInfo *targetRelInfo,
  						TupleTableSlot *slot,
  						ResultRelInfo **partRelInfo)
  {
  	ResultRelInfo *partrel;
  	TupleConversionMap *map;
  
  	/*
  	 * Lookup the target partition's ResultRelInfo.  If ExecFindPartition does
  	 * not find a valid partition for the tuple in 'slot' then an error is
  	 * raised.  An error may also be raised if the found partition is not a
  	 * valid target for INSERTs.  This is required since a partitioned table
  	 * UPDATE to another partition becomes a DELETE+INSERT.
  	 */
  	partrel = ExecFindPartition(mtstate, targetRelInfo, proute, slot, estate);
  
  	/*
  	 * If we're capturing transition tuples, we might need to convert from the
  	 * partition rowtype to root partitioned table's rowtype.  But if there
  	 * are no BEFORE triggers on the partition that could change the tuple, we
  	 * can just remember the original unconverted tuple to avoid a needless
  	 * round trip conversion.
  	 */
  	if (mtstate->mt_transition_capture != NULL)
  	{
  		bool		has_before_insert_row_trig;
  
  		has_before_insert_row_trig = (partrel->ri_TrigDesc &&
  									  partrel->ri_TrigDesc->trig_insert_before_row);
  
  		mtstate->mt_transition_capture->tcs_original_insert_tuple =
  			!has_before_insert_row_trig ? slot : NULL;
  	}
  
  	/*
  	 * Convert the tuple, if necessary.
  	 */
  	map = partrel->ri_RootToPartitionMap;
  	if (map != NULL)
  	{
  		TupleTableSlot *new_slot = partrel->ri_PartitionTupleSlot;
  
  		slot = execute_attr_map_slot(map->attrMap, slot, new_slot);
  	}
  
  	*partRelInfo = partrel;
  	return slot;
  }
  
  /* ----------------------------------------------------------------
   *	   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;
  	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;
  	/* for INSERT ... EXECUTE */
  	bool 		tsql_insert_exec = node->callStmt != NULL;
  	Tuplestorestate *tss;
  	TupleDesc 	tupdesc;
  	DestReceiver *dest = NULL;
  
  	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;
  
  	/*
  	 * On first call, fire BEFORE STATEMENT triggers before proceeding.
  	 */
  	if (node->fireBSTriggers)
  	{
  		fireBSTriggers(node);
  		node->fireBSTriggers = false;
  	}
  
  	/* Preload local variables */
  	resultRelInfo = node->resultRelInfo + node->mt_lastResultIndex;
  	subplanstate = outerPlanState(node);
  
  	/*
  	 * If we are here for INSERT ... EXECUTE, create a TuplestoreDestReceiver
  	 * and pass it to the procedure execution. The procedure execution will send
  	 * its result sets to the tuplestore via the receiver function.
  	 */
  	if (tsql_insert_exec)
  	{
  		tss = tuplestore_begin_heap(false, false, work_mem);
  		tupdesc = RelationGetDescr(resultRelInfo->ri_RelationDesc);
  		dest = CreateTuplestoreDestReceiver();
  		SetTuplestoreDestReceiverParams(dest, tss, CurrentMemoryContext, false, NULL, NULL);
  		dest->rStartup(dest, -1, tupdesc);
  
  		switch (nodeTag(node->callStmt))
  		{
  			case T_CallStmt:
  				ExecuteCallStmt((CallStmt *)node->callStmt,
  								pstate->state->es_param_list_info, false, dest);
  				break;
  			case T_DoStmt:
  				ExecuteDoStmtInsertExec((DoStmt *)node->callStmt, false, dest);
  				break;
  			default:
  				ereport(ERROR,
  						(errcode(ERRCODE_SYNTAX_ERROR),
  						 errmsg("Unrecognized stmt in INSERT EXEC")));
  				break;
  		}
  	}
  
  	/*
  	 * Fetch rows from subplan(s), and execute the required table modification
  	 * for each row.
  	 */
  	for (;;)
  	{
  		/*
  		 * Reset the per-output-tuple exprcontext.  This is needed because
  		 * triggers expect to use that context as workspace.  It's a bit ugly
  		 * to do this below the top level of the plan, however.  We might need
  		 * to rethink this later.
  		 */
  		ResetPerTupleExprContext(estate);
  
  		/*
  		 * Reset per-tuple memory context used for processing on conflict and
  		 * returning clauses, to free any expression evaluation storage
  		 * allocated in the previous cycle.
  		 */
  		if (pstate->ps_ExprContext)
  			ResetExprContext(pstate->ps_ExprContext);
  
  		if (tsql_insert_exec)
  		{
  			planSlot = MakeSingleTupleTableSlot(tupdesc, &TTSOpsMinimalTuple);
  			tuplestore_gettupleslot(tss, true, false, planSlot);
  		}
  		else
  			planSlot = ExecProcNode(subplanstate);
  
  		/* No more tuples to process? */
  		if (TupIsNull(planSlot))
  			break;
  
  		/*
  		 * When there are multiple result relations, each tuple contains a
  		 * junk column that gives the OID of the rel from which it came.
  		 * Extract it and select the correct result relation.
  		 */
  		if (AttributeNumberIsValid(node->mt_resultOidAttno))
  		{
  			Datum		datum;
  			bool		isNull;
  			Oid			resultoid;
  
  			datum = ExecGetJunkAttribute(planSlot, node->mt_resultOidAttno,
  										 &isNull);
  			if (isNull)
  				elog(ERROR, "tableoid is NULL");
  			resultoid = DatumGetObjectId(datum);
  
  			/* If it's not the same as last time, we need to locate the rel */
  			if (resultoid != node->mt_lastResultOid)
  				resultRelInfo = ExecLookupResultRelByOid(node, resultoid,
  														 false, true);
  		}
  
  		/*
  		 * If resultRelInfo->ri_usesFdwDirectModify is true, all we need to do
  		 * here is compute the RETURNING expressions.
  		 */
  		if (resultRelInfo->ri_usesFdwDirectModify)
  		{
  			Assert(resultRelInfo->ri_projectReturning);
  
  			/*
  			 * A scan slot containing the data that was actually inserted,
  			 * updated or deleted has already been made available to
  			 * ExecProcessReturning by IterateDirectModify, so no need to
  			 * provide it here.
  			 */
  			slot = ExecProcessReturning(resultRelInfo, NULL, planSlot);
  
  			return slot;
  		}
  
  		EvalPlanQualSetSlot(&node->mt_epqstate, planSlot);
  		slot = planSlot;
  
  		tupleid = NULL;
  		oldtuple = NULL;
  
  		/*
  		 * For UPDATE/DELETE, fetch the row identity info for the tuple to be
  		 * updated/deleted.  For a heap relation, that's a TID; otherwise we
  		 * may have a wholerow junk attr that carries the old tuple in toto.
  		 * Keep this in step with the part of ExecInitModifyTable that sets up
  		 * ri_RowIdAttNo.
  		 */
  		if (operation == CMD_UPDATE || operation == CMD_DELETE)
  		{
  			char		relkind;
  			Datum		datum;
  			bool		isNull;
  
  			relkind = resultRelInfo->ri_RelationDesc->rd_rel->relkind;
  			if (relkind == RELKIND_RELATION ||
  				relkind == RELKIND_MATVIEW ||
  				relkind == RELKIND_PARTITIONED_TABLE)
  			{
  				/* ri_RowIdAttNo refers to a ctid attribute */
  				Assert(AttributeNumberIsValid(resultRelInfo->ri_RowIdAttNo));
  				datum = ExecGetJunkAttribute(slot,
  											 resultRelInfo->ri_RowIdAttNo,
  											 &isNull);
  				/* shouldn't ever get a null result... */
  				if (isNull)
  					elog(ERROR, "ctid is NULL");
  
  				tupleid = (ItemPointer) DatumGetPointer(datum);
  				tuple_ctid = *tupleid;	/* be sure we don't free ctid!! */
  				tupleid = &tuple_ctid;
  			}
  
  			/*
  			 * Use the wholerow attribute, when available, to reconstruct the
  			 * old relation tuple.  The old tuple serves one or both of two
  			 * purposes: 1) it serves as the OLD tuple for row triggers, 2) it
  			 * provides values for any unchanged columns for the NEW tuple of
  			 * an UPDATE, because the subplan does not produce all the columns
  			 * of the target table.
  			 *
  			 * Note that the wholerow attribute does not carry system columns,
  			 * so foreign table triggers miss seeing those, except that we
  			 * know enough here to set t_tableOid.  Quite separately from
  			 * this, the FDW may fetch its own junk attrs to identify the row.
  			 *
  			 * Other relevant relkinds, currently limited to views, always
  			 * have a wholerow attribute.
  			 */
  			else if (AttributeNumberIsValid(resultRelInfo->ri_RowIdAttNo))
  			{
  				datum = ExecGetJunkAttribute(slot,
  											 resultRelInfo->ri_RowIdAttNo,
  											 &isNull);
  				/* shouldn't ever get a null result... */
  				if (isNull)
  					elog(ERROR, "wholerow is NULL");
  
  				oldtupdata.t_data = DatumGetHeapTupleHeader(datum);
  				oldtupdata.t_len =
  					HeapTupleHeaderGetDatumLength(oldtupdata.t_data);
  				ItemPointerSetInvalid(&(oldtupdata.t_self));
  				/* Historically, view triggers see invalid t_tableOid. */
  				oldtupdata.t_tableOid =
  					(relkind == RELKIND_VIEW) ? InvalidOid :
  					RelationGetRelid(resultRelInfo->ri_RelationDesc);
  
  				oldtuple = &oldtupdata;
  			}
  			else
  			{
  				/* Only foreign tables are allowed to omit a row-ID attr */
  				Assert(relkind == RELKIND_FOREIGN_TABLE);
  			}
  		}
  
  		switch (operation)
  		{
  			case CMD_INSERT:
  				/* Initialize projection info if first time for this table */
  				if (unlikely(!resultRelInfo->ri_projectNewInfoValid))
  					ExecInitInsertProjection(node, resultRelInfo);
  				slot = ExecGetInsertNewTuple(resultRelInfo, planSlot);
  				slot = ExecInsert(node, resultRelInfo, slot, planSlot,
  								  estate, node->canSetTag);
  				break;
  			case CMD_UPDATE:
  				/* Initialize projection info if first time for this table */
  				if (unlikely(!resultRelInfo->ri_projectNewInfoValid))
  					ExecInitUpdateProjection(node, resultRelInfo);
  
  				/*
  				 * Make the new tuple by combining plan's output tuple with
  				 * the old tuple being updated.
  				 */
  				oldSlot = resultRelInfo->ri_oldTupleSlot;
  				if (oldtuple != NULL)
  				{
  					/* Use the wholerow junk attr as the old tuple. */
  					ExecForceStoreHeapTuple(oldtuple, oldSlot, false);
  				}
  				else
  				{
  					/* Fetch the most recent version of old tuple. */
  					Relation	relation = resultRelInfo->ri_RelationDesc;
  
  					Assert(tupleid != NULL);
  					if (!table_tuple_fetch_row_version(relation, tupleid,
  													   SnapshotAny,
  													   oldSlot))
  						elog(ERROR, "failed to fetch tuple being updated");
  				}
  				slot = ExecGetUpdateNewTuple(resultRelInfo, planSlot,
  											 oldSlot);
  
  				/* Now apply the update. */
  				slot = ExecUpdate(node, resultRelInfo, tupleid, oldtuple, slot,
  								  planSlot, &node->mt_epqstate, estate,
  								  node->canSetTag);
  				break;
  			case CMD_DELETE:
  				slot = ExecDelete(node, resultRelInfo, tupleid, oldtuple,
  								  planSlot, &node->mt_epqstate, estate,
  								  true, /* processReturning */
  								  node->canSetTag,
  								  false,	/* changingPart */
  								  NULL, NULL);
  				break;
  			default:
  				elog(ERROR, "unknown operation");
  				break;
  		}
  
  		if(tsql_insert_exec)
  			ExecDropSingleTupleTableSlot(planSlot);
  
  		/*
  		 * If we got a RETURNING result, return it to caller.  We'll continue
  		 * the work on next call.
  		 */
  		if (slot)
  			return slot;
  	}
  
  	if (tsql_insert_exec && dest)
  	{
  		dest->rShutdown(dest);
  		dest->rDestroy(dest);
  	}
  
  	/*
  	 * Insert remaining tuples for batch insert.
  	 */
  	if (proute)
  		relinfos = estate->es_tuple_routing_result_relations;
  	else
  		relinfos = estate->es_opened_result_relations;
  
  	foreach(lc, relinfos)
  	{
  		resultRelInfo = lfirst(lc);
  		if (resultRelInfo->ri_NumSlots > 0)
  			ExecBatchInsert(node, resultRelInfo,
  							resultRelInfo->ri_Slots,
  							resultRelInfo->ri_PlanSlots,
  							resultRelInfo->ri_NumSlots,
  							estate, node->canSetTag);
  	}
  
  	/* Try to see if IOT exists on the action. fireISTriggers() should return
  	 * IOT_NOT_REQUIRED if there does not exist on the relation and action.
  	 * Otherwise, this should fire the IOT or recognize the IOT has already been
  	 * fired.
  	 * 
  	 * IOT should be fired after execution is done
  	 */
  	if (node->fireISTriggers == IOT_NOT_FIRED)
  	{
  		node->fireISTriggers = fireISTriggers(node);
  	}
  
  	/* If IOT is already fired, bail out */
  	if (node->fireISTriggers == IOT_FIRED)
  	{
  		node->mt_done = true;
  		return NULL;
  	}
  
  	/*
  	 * We're done, but fire AFTER STATEMENT triggers before exiting.
  	 */
  	fireASTriggers(node);
  
  	node->mt_done = true;
  
  	return NULL;
  }
  
  /*
   * ExecLookupResultRelByOid
   * 		If the table with given OID is among the result relations to be
   * 		updated by the given ModifyTable node, return its ResultRelInfo.
   *
   * If not found, return NULL if missing_ok, else raise error.
   *
   * If update_cache is true, then upon successful lookup, update the node's
   * one-element cache.  ONLY ExecModifyTable may pass true for this.
   */
  ResultRelInfo *
  ExecLookupResultRelByOid(ModifyTableState *node, Oid resultoid,
  						 bool missing_ok, bool update_cache)
  {
  	if (node->mt_resultOidHash)
  	{
  		/* Use the pre-built hash table to locate the rel */
  		MTTargetRelLookup *mtlookup;
  
  		mtlookup = (MTTargetRelLookup *)
  			hash_search(node->mt_resultOidHash, &resultoid, HASH_FIND, NULL);
  		if (mtlookup)
  		{
  			if (update_cache)
  			{
  				node->mt_lastResultOid = resultoid;
  				node->mt_lastResultIndex = mtlookup->relationIndex;
  			}
  			return node->resultRelInfo + mtlookup->relationIndex;
  		}
  	}
  	else
  	{
  		/* With few target rels, just search the ResultRelInfo array */
  		for (int ndx = 0; ndx < node->mt_nrels; ndx++)
  		{
  			ResultRelInfo *rInfo = node->resultRelInfo + ndx;
  
  			if (RelationGetRelid(rInfo->ri_RelationDesc) == resultoid)
  			{
  				if (update_cache)
  				{
  					node->mt_lastResultOid = resultoid;
  					node->mt_lastResultIndex = ndx;
  				}
  				return rInfo;
  			}
  		}
  	}
  
  	if (!missing_ok)
  		elog(ERROR, "incorrect result relation OID %u", resultoid);
  	return NULL;
  }
  
  /* ----------------------------------------------------------------
   *		ExecInitModifyTable
   * ----------------------------------------------------------------
   */
  ModifyTableState *
  ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
  {
  	ModifyTableState *mtstate;
  	Plan	   *subplan = outerPlan(node);
  	CmdType		operation = node->operation;
  	int			nrels = list_length(node->resultRelations);
  	ResultRelInfo *resultRelInfo;
  	List	   *arowmarks;
  	ListCell   *l;
  	int			i;
  	Relation	rel;
  
  	/* check for unsupported flags */
  	Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
  
  	/*
  	 * create state structure
  	 */
  	mtstate = makeNode(ModifyTableState);
  	mtstate->ps.plan = (Plan *) node;
  	mtstate->ps.state = estate;
  	mtstate->ps.ExecProcNode = ExecModifyTable;
  
  	mtstate->operation = operation;
  	mtstate->canSetTag = node->canSetTag;
  	mtstate->mt_done = false;
  
  	mtstate->mt_nrels = nrels;
  	mtstate->resultRelInfo = (ResultRelInfo *)
  		palloc(nrels * sizeof(ResultRelInfo));
  
  	mtstate->callStmt = node->callStmt;
  
  	/*----------
  	 * Resolve the target relation. This is the same as:
  	 *
  	 * - the relation for which we will fire FOR STATEMENT triggers,
  	 * - the relation into whose tuple format all captured transition tuples
  	 *   must be converted, and
  	 * - the root partitioned table used for tuple routing.
  	 *
  	 * If it's a partitioned table, the root partition doesn't appear
  	 * elsewhere in the plan and its RT index is given explicitly in
  	 * node->rootRelation.  Otherwise (i.e. table inheritance) the target
  	 * relation is the first relation in the node->resultRelations list.
  	 *----------
  	 */
  	if (node->rootRelation > 0)
  	{
  		mtstate->rootResultRelInfo = makeNode(ResultRelInfo);
  		ExecInitResultRelation(estate, mtstate->rootResultRelInfo,
  							   node->rootRelation);
  	}
  	else
  	{
  		mtstate->rootResultRelInfo = mtstate->resultRelInfo;
  		ExecInitResultRelation(estate, mtstate->resultRelInfo,
  							   linitial_int(node->resultRelations));
  	}
  
  	/* set up epqstate with dummy subplan data for the moment */
  	EvalPlanQualInit(&mtstate->mt_epqstate, estate, NULL, NIL, node->epqParam);
  	mtstate->fireBSTriggers = true;
  	mtstate->fireISTriggers = IOT_NOT_FIRED;
  
  	/*
  	 * Build state for collecting transition tuples.  This requires having a
  	 * valid trigger query context, so skip it in explain-only mode.
  	 */
  	if (!(eflags & EXEC_FLAG_EXPLAIN_ONLY))
  		ExecSetupTransitionCaptureState(mtstate, estate);
  
  	/*
  	 * Open all the result relations and initialize the ResultRelInfo structs.
  	 * (But root relation was initialized above, if it's part of the array.)
  	 * We must do this before initializing the subplan, because direct-modify
  	 * FDWs expect their ResultRelInfos to be available.
  	 */
  	resultRelInfo = mtstate->resultRelInfo;
  	i = 0;
  	foreach(l, node->resultRelations)
  	{
  		Index		resultRelation = lfirst_int(l);
  
  		if (resultRelInfo != mtstate->rootResultRelInfo)
  		{
  			ExecInitResultRelation(estate, resultRelInfo, resultRelation);
  
  			/*
  			 * For child result relations, store the root result relation
  			 * pointer.  We do so for the convenience of places that want to
  			 * look at the query's original target relation but don't have the
  			 * mtstate handy.
  			 */
  			resultRelInfo->ri_RootResultRelInfo = mtstate->rootResultRelInfo;
  		}
  
  		/* Initialize the usesFdwDirectModify flag */
  		resultRelInfo->ri_usesFdwDirectModify = bms_is_member(i,
  															  node->fdwDirectModifyPlans);
  
  		/*
  		 * Verify result relation is a valid target for the current operation
  		 */
  		CheckValidResultRel(resultRelInfo, operation);
  
  		resultRelInfo++;
  		i++;
  	}
  
  	/*
  	 * Now we may initialize the subplan.
  	 */
  	outerPlanState(mtstate) = ExecInitNode(subplan, estate, eflags);
  
  	/*
  	 * Do additional per-result-relation initialization.
  	 */
  	for (i = 0; i < nrels; i++)
  	{
  		resultRelInfo = &mtstate->resultRelInfo[i];
  
  		/* Let FDWs init themselves for foreign-table result rels */
  		if (!resultRelInfo->ri_usesFdwDirectModify &&
  			resultRelInfo->ri_FdwRoutine != NULL &&
  			resultRelInfo->ri_FdwRoutine->BeginForeignModify != NULL)
  		{
  			List	   *fdw_private = (List *) list_nth(node->fdwPrivLists, i);
  
  			resultRelInfo->ri_FdwRoutine->BeginForeignModify(mtstate,
  															 resultRelInfo,
  															 fdw_private,
  															 i,
  															 eflags);
  		}
  
  		/*
  		 * For UPDATE/DELETE, find the appropriate junk attr now, either a
  		 * 'ctid' or 'wholerow' attribute depending on relkind.  For foreign
  		 * tables, the FDW might have created additional junk attr(s), but
  		 * those are no concern of ours.
  		 */
  		if (operation == CMD_UPDATE || operation == CMD_DELETE)
  		{
  			char		relkind;
  
  			relkind = resultRelInfo->ri_RelationDesc->rd_rel->relkind;
  			if (relkind == RELKIND_RELATION ||
  				relkind == RELKIND_MATVIEW ||
  				relkind == RELKIND_PARTITIONED_TABLE)
  			{
  				resultRelInfo->ri_RowIdAttNo =
  					ExecFindJunkAttributeInTlist(subplan->targetlist, "ctid");
  				if (!AttributeNumberIsValid(resultRelInfo->ri_RowIdAttNo))
  					elog(ERROR, "could not find junk ctid column");
  			}
  			else if (relkind == RELKIND_FOREIGN_TABLE)
  			{
  				/*
  				 * When there is a row-level trigger, there should be a
  				 * wholerow attribute.  We also require it to be present in
  				 * UPDATE, so we can get the values of unchanged columns.
  				 */
  				resultRelInfo->ri_RowIdAttNo =
  					ExecFindJunkAttributeInTlist(subplan->targetlist,
  												 "wholerow");
  				if (mtstate->operation == CMD_UPDATE &&
  					!AttributeNumberIsValid(resultRelInfo->ri_RowIdAttNo))
  					elog(ERROR, "could not find junk wholerow column");
  			}
  			else
  			{
  				/* Other valid target relkinds must provide wholerow */
  				resultRelInfo->ri_RowIdAttNo =
  					ExecFindJunkAttributeInTlist(subplan->targetlist,
  												 "wholerow");
  				if (!AttributeNumberIsValid(resultRelInfo->ri_RowIdAttNo))
  					elog(ERROR, "could not find junk wholerow column");
  			}
  		}
  	}
  
  	/*
  	 * If this is an inherited update/delete, there will be a junk attribute
  	 * named "tableoid" present in the subplan's targetlist.  It will be used
  	 * to identify the result relation for a given tuple to be
  	 * updated/deleted.
  	 */
  	mtstate->mt_resultOidAttno =
  		ExecFindJunkAttributeInTlist(subplan->targetlist, "tableoid");
  	Assert(AttributeNumberIsValid(mtstate->mt_resultOidAttno) || nrels == 1);
  	mtstate->mt_lastResultOid = InvalidOid; /* force lookup at first tuple */
  	mtstate->mt_lastResultIndex = 0;	/* must be zero if no such attr */
  
  	/* Get the root target relation */
  	rel = mtstate->rootResultRelInfo->ri_RelationDesc;
  
  	/*
  	 * Build state for tuple routing if it's a partitioned INSERT.  An UPDATE
  	 * might need this too, but only if it actually moves tuples between
  	 * partitions; in that case setup is done by ExecCrossPartitionUpdate.
  	 */
  	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE &&
  		operation == CMD_INSERT)
  		mtstate->mt_partition_tuple_routing =
  			ExecSetupPartitionTupleRouting(estate, rel);
  
  	/*
  	 * Initialize any WITH CHECK OPTION constraints if needed.
  	 */
  	resultRelInfo = mtstate->resultRelInfo;
  	foreach(l, node->withCheckOptionLists)
  	{
  		List	   *wcoList = (List *) lfirst(l);
  		List	   *wcoExprs = NIL;
  		ListCell   *ll;
  
  		foreach(ll, wcoList)
  		{
  			WithCheckOption *wco = (WithCheckOption *) lfirst(ll);
  			ExprState  *wcoExpr = ExecInitQual((List *) wco->qual,
  											   &mtstate->ps);
  
  			wcoExprs = lappend(wcoExprs, wcoExpr);
  		}
  
  		resultRelInfo->ri_WithCheckOptions = wcoList;
  		resultRelInfo->ri_WithCheckOptionExprs = wcoExprs;
  		resultRelInfo++;
  	}
  
  	/*
  	 * Initialize RETURNING projections if needed.
  	 */
  	if (node->returningLists)
  	{
  		TupleTableSlot *slot;
  		ExprContext *econtext;
  
  		/*
  		 * Initialize result tuple slot and assign its rowtype using the first
  		 * RETURNING list.  We assume the rest will look the same.
  		 */
  		mtstate->ps.plan->targetlist = (List *) linitial(node->returningLists);
  
  		/* Set up a slot for the output of the RETURNING projection(s) */
  		ExecInitResultTupleSlotTL(&mtstate->ps, &TTSOpsVirtual);
  		slot = mtstate->ps.ps_ResultTupleSlot;
  
  		/* Need an econtext too */
  		if (mtstate->ps.ps_ExprContext == NULL)
  			ExecAssignExprContext(estate, &mtstate->ps);
  		econtext = mtstate->ps.ps_ExprContext;
  
  		/*
  		 * Build a projection for each result rel.
  		 */
  		resultRelInfo = mtstate->resultRelInfo;
  		foreach(l, node->returningLists)
  		{
  			List	   *rlist = (List *) lfirst(l);
  
  			resultRelInfo->ri_returningList = rlist;
  			resultRelInfo->ri_projectReturning =
  				ExecBuildProjectionInfo(rlist, econtext, slot, &mtstate->ps,
  										resultRelInfo->ri_RelationDesc->rd_att);
  			resultRelInfo++;
  		}
  	}
  	else
  	{
  		/*
  		 * We still must construct a dummy result tuple type, because InitPlan
  		 * expects one (maybe should change that?).
  		 */
  		mtstate->ps.plan->targetlist = NIL;
  		ExecInitResultTypeTL(&mtstate->ps);
  
  		mtstate->ps.ps_ExprContext = NULL;
  	}
  
  	/* Set the list of arbiter indexes if needed for ON CONFLICT */
  	resultRelInfo = mtstate->resultRelInfo;
  	if (node->onConflictAction != ONCONFLICT_NONE)
  	{
  		/* insert may only have one relation, inheritance is not expanded */
  		Assert(nrels == 1);
  		resultRelInfo->ri_onConflictArbiterIndexes = node->arbiterIndexes;
  	}
  
  	/*
  	 * If needed, Initialize target list, projection and qual for ON CONFLICT
  	 * DO UPDATE.
  	 */
  	if (node->onConflictAction == ONCONFLICT_UPDATE)
  	{
  		OnConflictSetState *onconfl = makeNode(OnConflictSetState);
  		ExprContext *econtext;
  		TupleDesc	relationDesc;
  
  		/* already exists if created by RETURNING processing above */
  		if (mtstate->ps.ps_ExprContext == NULL)
  			ExecAssignExprContext(estate, &mtstate->ps);
  
  		econtext = mtstate->ps.ps_ExprContext;
  		relationDesc = resultRelInfo->ri_RelationDesc->rd_att;
  
  		/* create state for DO UPDATE SET operation */
  		resultRelInfo->ri_onConflict = onconfl;
  
  		/* initialize slot for the existing tuple */
  		onconfl->oc_Existing =
  			table_slot_create(resultRelInfo->ri_RelationDesc,
  							  &mtstate->ps.state->es_tupleTable);
  
  		/*
  		 * Create the tuple slot for the UPDATE SET projection. We want a slot
  		 * of the table's type here, because the slot will be used to insert
  		 * into the table, and for RETURNING processing - which may access
  		 * system attributes.
  		 */
  		onconfl->oc_ProjSlot =
  			table_slot_create(resultRelInfo->ri_RelationDesc,
  							  &mtstate->ps.state->es_tupleTable);
  
  		/* build UPDATE SET projection state */
  		onconfl->oc_ProjInfo =
  			ExecBuildUpdateProjection(node->onConflictSet,
  									  true,
  									  node->onConflictCols,
  									  relationDesc,
  									  econtext,
  									  onconfl->oc_ProjSlot,
  									  &mtstate->ps);
  
  		/* initialize state to evaluate the WHERE clause, if any */
  		if (node->onConflictWhere)
  		{
  			ExprState  *qualexpr;
  
  			qualexpr = ExecInitQual((List *) node->onConflictWhere,
  									&mtstate->ps);
  			onconfl->oc_WhereClause = qualexpr;
  		}
  	}
  
  	/*
  	 * If we have any secondary relations in an UPDATE or DELETE, they need to
  	 * be treated like non-locked relations in SELECT FOR UPDATE, ie, the
  	 * EvalPlanQual mechanism needs to be told about them.  Locate the
  	 * relevant ExecRowMarks.
  	 */
  	arowmarks = NIL;
  	foreach(l, node->rowMarks)
  	{
  		PlanRowMark *rc = lfirst_node(PlanRowMark, l);
  		ExecRowMark *erm;
  		ExecAuxRowMark *aerm;
  
  		/* ignore "parent" rowmarks; they are irrelevant at runtime */
  		if (rc->isParent)
  			continue;
  
  		/* Find ExecRowMark and build ExecAuxRowMark */
  		erm = ExecFindRowMark(estate, rc->rti, false);
  		aerm = ExecBuildAuxRowMark(erm, subplan->targetlist);
  		arowmarks = lappend(arowmarks, aerm);
  	}
  
  	EvalPlanQualSetPlan(&mtstate->mt_epqstate, subplan, arowmarks);
  
  	/*
  	 * If there are a lot of result relations, use a hash table to speed the
  	 * lookups.  If there are not a lot, a simple linear search is faster.
  	 *
  	 * It's not clear where the threshold is, but try 64 for starters.  In a
  	 * debugging build, use a small threshold so that we get some test
  	 * coverage of both code paths.
  	 */
  #ifdef USE_ASSERT_CHECKING
  #define MT_NRELS_HASH 4
  #else
  #define MT_NRELS_HASH 64
  #endif
  	if (nrels >= MT_NRELS_HASH)
  	{
  		HASHCTL		hash_ctl;
  
  		hash_ctl.keysize = sizeof(Oid);
  		hash_ctl.entrysize = sizeof(MTTargetRelLookup);
  		hash_ctl.hcxt = CurrentMemoryContext;
  		mtstate->mt_resultOidHash =
  			hash_create("ModifyTable target hash",
  						nrels, &hash_ctl,
  						HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
  		for (i = 0; i < nrels; i++)
  		{
  			Oid			hashkey;
  			MTTargetRelLookup *mtlookup;
  			bool		found;
  
  			resultRelInfo = &mtstate->resultRelInfo[i];
  			hashkey = RelationGetRelid(resultRelInfo->ri_RelationDesc);
  			mtlookup = (MTTargetRelLookup *)
  				hash_search(mtstate->mt_resultOidHash, &hashkey,
  							HASH_ENTER, &found);
  			Assert(!found);
  			mtlookup->relationIndex = i;
  		}
  	}
  	else
  		mtstate->mt_resultOidHash = NULL;
  
  	/*
  	 * Determine if the FDW supports batch insert and determine the batch size
  	 * (a FDW may support batching, but it may be disabled for the
  	 * server/table).
  	 *
  	 * We only do this for INSERT, so that for UPDATE/DELETE the batch size
  	 * remains set to 0.
  	 */
  	if (operation == CMD_INSERT)
  	{
  		/* insert may only have one relation, inheritance is not expanded */
  		Assert(nrels == 1);
  		resultRelInfo = mtstate->resultRelInfo;
  		if (!resultRelInfo->ri_usesFdwDirectModify &&
  			resultRelInfo->ri_FdwRoutine != NULL &&
  			resultRelInfo->ri_FdwRoutine->GetForeignModifyBatchSize &&
  			resultRelInfo->ri_FdwRoutine->ExecForeignBatchInsert)
  		{
  			resultRelInfo->ri_BatchSize =
  				resultRelInfo->ri_FdwRoutine->GetForeignModifyBatchSize(resultRelInfo);
  			Assert(resultRelInfo->ri_BatchSize >= 1);
  		}
  		else
  			resultRelInfo->ri_BatchSize = 1;
  	}
  
  	/*
  	 * Lastly, if this is not the primary (canSetTag) ModifyTable node, add it
  	 * to estate->es_auxmodifytables so that it will be run to completion by
  	 * ExecPostprocessPlan.  (It'd actually work fine to add the primary
  	 * ModifyTable node too, but there's no need.)  Note the use of lcons not
  	 * lappend: we need later-initialized ModifyTable nodes to be shut down
  	 * before earlier ones.  This ensures that we don't throw away RETURNING
  	 * rows that need to be seen by a later CTE subplan.
  	 */
  	if (!mtstate->canSetTag)
  		estate->es_auxmodifytables = lcons(mtstate,
  										   estate->es_auxmodifytables);
  
  	return mtstate;
  }
  
  /* ----------------------------------------------------------------
   *		ExecEndModifyTable
   *
   *		Shuts down the plan.
   *
   *		Returns nothing of interest.
   * ----------------------------------------------------------------
   */
  void
  ExecEndModifyTable(ModifyTableState *node)
  {
  	int			i;
  
  	/*
  	 * Allow any FDWs to shut down
  	 */
  	for (i = 0; i < node->mt_nrels; i++)
  	{
  		int			j;
  		ResultRelInfo *resultRelInfo = node->resultRelInfo + i;
  
  		if (!resultRelInfo->ri_usesFdwDirectModify &&
  			resultRelInfo->ri_FdwRoutine != NULL &&
  			resultRelInfo->ri_FdwRoutine->EndForeignModify != NULL)
  			resultRelInfo->ri_FdwRoutine->EndForeignModify(node->ps.state,
  														   resultRelInfo);
  
  		/*
  		 * Cleanup the initialized batch slots. This only matters for FDWs
  		 * with batching, but the other cases will have ri_NumSlotsInitialized
  		 * == 0.
  		 */
  		for (j = 0; j < resultRelInfo->ri_NumSlotsInitialized; j++)
  		{
  			ExecDropSingleTupleTableSlot(resultRelInfo->ri_Slots[j]);
  			ExecDropSingleTupleTableSlot(resultRelInfo->ri_PlanSlots[j]);
  		}
  	}
  
  	/*
  	 * Close all the partitioned tables, leaf partitions, and their indices
  	 * and release the slot used for tuple routing, if set.
  	 */
  	if (node->mt_partition_tuple_routing)
  	{
  		ExecCleanupTupleRouting(node, node->mt_partition_tuple_routing);
  
  		if (node->mt_root_tuple_slot)
  			ExecDropSingleTupleTableSlot(node->mt_root_tuple_slot);
  	}
  
  	/*
  	 * Free the exprcontext
  	 */
  	ExecFreeExprContext(&node->ps);
  
  	/*
  	 * clean out the tuple table
  	 */
  	if (node->ps.ps_ResultTupleSlot)
  		ExecClearTuple(node->ps.ps_ResultTupleSlot);
  
  	/*
  	 * Terminate EPQ execution if active
  	 */
  	EvalPlanQualEnd(&node->mt_epqstate);
  
  	/*
  	 * shut down subplan
  	 */
  	ExecEndNode(outerPlanState(node));
  }
  
  void
  ExecReScanModifyTable(ModifyTableState *node)
  {
  	/*
  	 * Currently, we don't need to support rescan on ModifyTable nodes. The
  	 * semantics of that would be a bit debatable anyway.
  	 */
  	elog(ERROR, "ExecReScanModifyTable is not implemented");
  }
  