Merge pull request #1764 from citusdata/relcache_leak

Fix a relcache reference leak in stats collection.

src/backend/distributed/utils/statistics_collection.c

@@ -397,6 +397,7 @@ DistributedTablesSize(List *distTableOids)
 		if (PartitionMethod(relationId) == DISTRIBUTE_BY_HASH &&
 			!SingleReplicatedTable(relationId))
 		{
+			heap_close(relation, AccessShareLock);
 			continue;
 		}