Fix Reference Table Check for CDC (#7025)

Previously reference table check only looked at `partition method =
'n'`. This PR adds `replication model = 't'` to that.

src/backend/distributed/cdc/cdc_decoder.c

@@ -203,8 +203,7 @@ AddShardIdToHashTable(uint64 shardId, ShardIdHashEntry *entry)
 {
 	entry->shardId = shardId;
 	entry->distributedTableId = CdcLookupShardRelationFromCatalog(shardId, true);
-	entry->isReferenceTable = CdcPartitionMethodViaCatalog(entry->distributedTableId) ==
-							  'n';
+	entry->isReferenceTable = CdcIsReferenceTableViaCatalog(entry->distributedTableId);
 	return entry->distributedTableId;
 }
 
@@ -361,12 +360,14 @@ GetTupleForTargetSchemaForCdc(HeapTuple sourceRelationTuple,
 			targetNulls[targetIndex] = true;
 			targetIndex++;
 		}
+
 		/* If this source attribute has been dropped, just skip this source attribute.*/
 		else if (TupleDescAttr(sourceRelDesc, sourceIndex)->attisdropped)
 		{
 			sourceIndex++;
 			continue;
 		}
+
 		/* If both source and target attributes are not dropped, add the attribute field to targetValues. */
 		else if (sourceIndex < sourceRelDesc->natts)
 		{

src/backend/distributed/cdc/cdc_decoder_utils.c

@@ -331,16 +331,16 @@ CdcPgDistPartitionTupleViaCatalog(Oid relationId)
 
 
 /*
- * CdcPartitionMethodViaCatalog gets a relationId and returns the partition
- * method column from pg_dist_partition via reading from catalog.
+ * CdcIsReferenceTableViaCatalog gets a relationId and returns true if the relation
+ * is a reference table and false otherwise.
  */
 char
-CdcPartitionMethodViaCatalog(Oid relationId)
+CdcIsReferenceTableViaCatalog(Oid relationId)
 {
 	HeapTuple partitionTuple = CdcPgDistPartitionTupleViaCatalog(relationId);
 	if (!HeapTupleIsValid(partitionTuple))
 	{
-		return DISTRIBUTE_BY_INVALID;
+		return false;
 	}
 
 	Datum datumArray[Natts_pg_dist_partition];
@@ -351,21 +351,32 @@ CdcPartitionMethodViaCatalog(Oid relationId)
 	TupleDesc tupleDescriptor = RelationGetDescr(pgDistPartition);
 	heap_deform_tuple(partitionTuple, tupleDescriptor, datumArray, isNullArray);
 
-	if (isNullArray[Anum_pg_dist_partition_partmethod - 1])
+	if (isNullArray[Anum_pg_dist_partition_partmethod - 1] ||
+		isNullArray[Anum_pg_dist_partition_repmodel - 1])
 	{
-		/* partition method cannot be NULL, still let's make sure */
+		/*
+		 * partition method and replication model cannot be NULL,
+		 * still let's make sure
+		 */
 		heap_freetuple(partitionTuple);
 		table_close(pgDistPartition, NoLock);
-		return DISTRIBUTE_BY_INVALID;
+		return false;
 	}
 
 	Datum partitionMethodDatum = datumArray[Anum_pg_dist_partition_partmethod - 1];
 	char partitionMethodChar = DatumGetChar(partitionMethodDatum);
 
+	Datum replicationModelDatum = datumArray[Anum_pg_dist_partition_repmodel - 1];
+	char replicationModelChar = DatumGetChar(replicationModelDatum);
+
 	heap_freetuple(partitionTuple);
 	table_close(pgDistPartition, NoLock);
 
-	return partitionMethodChar;
+	/*
+	 * A table is a reference table when its partition method is 'none'
+	 * and replication model is 'two phase commit'
+	 */
+	return partitionMethodChar == 'n' && replicationModelChar == 't';
 }
 
 

src/backend/distributed/cdc/cdc_decoder_utils.h

@@ -25,7 +25,7 @@ uint64 CdcExtractShardIdFromTableName(const char *tableName, bool missingOk);
 
 Oid CdcLookupShardRelationFromCatalog(int64 shardId, bool missingOk);
 
-char CdcPartitionMethodViaCatalog(Oid relationId);
+char CdcIsReferenceTableViaCatalog(Oid relationId);
 
 bool CdcCitusHasBeenLoaded(void);