Modify the way ExecMergeMatched() detects moved partitions

Use tupleid for ROW_REF_TID as in upsteam.  Use &context->tmfd.ctid for
ROW_REF_ROWID as in OrioleDB.

Author: akorotkov

src/backend/executor/nodeModifyTable.c

@@ -2832,6 +2832,7 @@ ExecMergeMatched(ModifyTableContext *context, ResultRelInfo *resultRelInfo,
 				{
 					Relation	resultRelationDesc;
 					TupleTableSlot *epqslot;
+					ItemPointer movedPartitionCheckCtid;
 
 					/*
 					 * The target tuple was concurrently updated by some other
@@ -2857,7 +2858,11 @@ ExecMergeMatched(ModifyTableContext *context, ResultRelInfo *resultRelInfo,
 					 * the tuple moved, and setting our current
 					 * resultRelInfo to that.
 					 */
-					if (ItemPointerIndicatesMovedPartitions(&context->tmfd.ctid))
+					if (resultRelInfo->ri_RowRefType == ROW_REF_TID)
+						movedPartitionCheckCtid = (ItemPointer) tupleid;
+					else
+						movedPartitionCheckCtid = &context->tmfd.ctid;
+					if (ItemPointerIndicatesMovedPartitions(movedPartitionCheckCtid))
 						ereport(ERROR,
 								(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
 								 errmsg("tuple to be merged was already moved to another partition due to concurrent update")));