@@ -13489,9 +13489,20 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
1348913489/*
1349013490 * Prevent circularity by seeing if rel is a partition of attachrel. (In
1349113491 * particular, this disallows making a rel a partition of itself.)
13492+ *
13493+ * We do that by checking if rel is a member of the list of attachRel's
13494+ * partitions provided the latter is partitioned at all. We want to avoid
13495+ * having to construct this list again, so we request the strongest lock
13496+ * on all partitions. We need the strongest lock, because we may decide
13497+ * to scan them if we find out that the table being attached (or its leaf
13498+ * partitions) may contain rows that violate the partition constraint.
13499+ * If the table has a constraint that would prevent such rows, which by
13500+ * definition is present in all the partitions, we need not scan the
13501+ * table, nor its partitions. But we cannot risk a deadlock by taking a
13502+ * weaker lock now and the stronger one only when needed.
1349213503 */
1349313504attachrel_children = find_all_inheritors (RelationGetRelid (attachrel ),
13494- AccessShareLock ,NULL );
13505+ AccessExclusiveLock ,NULL );
1349513506if (list_member_oid (attachrel_children ,RelationGetRelid (rel )))
1349613507ereport (ERROR ,
1349713508(errcode (ERRCODE_DUPLICATE_TABLE ),
@@ -13694,17 +13705,9 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
1369413705else
1369513706{
1369613707/* Constraints proved insufficient, so we need to scan the table. */
13697- List * all_parts ;
1369813708ListCell * lc ;
1369913709
13700- /* Take an exclusive lock on the partitions to be checked */
13701- if (attachrel -> rd_rel -> relkind == RELKIND_PARTITIONED_TABLE )
13702- all_parts = find_all_inheritors (RelationGetRelid (attachrel ),
13703- AccessExclusiveLock ,NULL );
13704- else
13705- all_parts = list_make1_oid (RelationGetRelid (attachrel ));
13706-
13707- foreach (lc ,all_parts )
13710+ foreach (lc ,attachrel_children )
1370813711{
1370913712AlteredTableInfo * tab ;
1371013713Oid part_relid = lfirst_oid (lc );