3 files changed, 108 insertions, 0 deletions
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 2f5bde60539..3c0bd7b104f 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -10329,6 +10329,39 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel)
 		}
 	}
 
+	/*
+	 * If the parent has an OID column, so must the child, and we'd better
+	 * update the child's attinhcount and attislocal the same as for normal
+	 * columns.  We needn't check data type or not-nullness though.
+	 */
+	if (tupleDesc->tdhasoid)
+	{
+		/*
+		 * Here we match by column number not name; the match *must* be the
+		 * system column, not some random column named "oid".
+		 */
+		tuple = SearchSysCacheCopy2(ATTNUM,
+							   ObjectIdGetDatum(RelationGetRelid(child_rel)),
+									Int16GetDatum(ObjectIdAttributeNumber));
+		if (HeapTupleIsValid(tuple))
+		{
+			Form_pg_attribute childatt = (Form_pg_attribute) GETSTRUCT(tuple);
+
+			/* See comments above; these changes should be the same */
+			childatt->attinhcount++;
+			simple_heap_update(attrrel, &tuple->t_self, tuple);
+			CatalogUpdateIndexes(attrrel, tuple);
+			heap_freetuple(tuple);
+		}
+		else
+		{
+			ereport(ERROR,
+					(errcode(ERRCODE_DATATYPE_MISMATCH),
+					 errmsg("child table is missing column \"%s\"",
+							"oid")));
+		}
+	}
+
 	heap_close(attrrel, RowExclusiveLock);
 }
 
diff --git a/src/test/regress/expected/inherit.out b/src/test/regress/expected/inherit.out
index 79e9969d574..50c65be4596 100644
--- a/src/test/regress/expected/inherit.out
+++ b/src/test/regress/expected/inherit.out
@@ -612,6 +612,55 @@ select * from d;
  32 | one | two | three
 (1 row)
 
+-- check that oid column is handled properly during alter table inherit
+create table oid_parent (a int) with oids;
+create table oid_child () inherits (oid_parent);
+select attinhcount, attislocal from pg_attribute
+  where attrelid = 'oid_child'::regclass and attname = 'oid';
+ attinhcount | attislocal 
+-------------+------------
+           1 | f
+(1 row)
+
+drop table oid_child;
+create table oid_child (a int) without oids;
+alter table oid_child inherit oid_parent;  -- fail
+ERROR:  table "oid_child" without OIDs cannot inherit from table "oid_parent" with OIDs
+alter table oid_child set with oids;
+select attinhcount, attislocal from pg_attribute
+  where attrelid = 'oid_child'::regclass and attname = 'oid';
+ attinhcount | attislocal 
+-------------+------------
+           0 | t
+(1 row)
+
+alter table oid_child inherit oid_parent;
+select attinhcount, attislocal from pg_attribute
+  where attrelid = 'oid_child'::regclass and attname = 'oid';
+ attinhcount | attislocal 
+-------------+------------
+           1 | t
+(1 row)
+
+alter table oid_child set without oids;  -- fail
+ERROR:  cannot drop inherited column "oid"
+alter table oid_parent set without oids;
+select attinhcount, attislocal from pg_attribute
+  where attrelid = 'oid_child'::regclass and attname = 'oid';
+ attinhcount | attislocal 
+-------------+------------
+           0 | t
+(1 row)
+
+alter table oid_child set without oids;
+select attinhcount, attislocal from pg_attribute
+  where attrelid = 'oid_child'::regclass and attname = 'oid';
+ attinhcount | attislocal 
+-------------+------------
+(0 rows)
+
+drop table oid_parent cascade;
+NOTICE:  drop cascades to table oid_child
 -- Test non-inheritable parent constraints
 create table p1(ff1 int);
 alter table p1 add constraint p1chk check (ff1 > 0) no inherit;
diff --git a/src/test/regress/sql/inherit.sql b/src/test/regress/sql/inherit.sql
index f45aab1ac69..f4ec72856e8 100644
--- a/src/test/regress/sql/inherit.sql
+++ b/src/test/regress/sql/inherit.sql
@@ -145,6 +145,32 @@ insert into d values('test','one','two','three');
 alter table a alter column aa type integer using bit_length(aa);
 select * from d;
 
+-- check that oid column is handled properly during alter table inherit
+create table oid_parent (a int) with oids;
+
+create table oid_child () inherits (oid_parent);
+select attinhcount, attislocal from pg_attribute
+  where attrelid = 'oid_child'::regclass and attname = 'oid';
+drop table oid_child;
+
+create table oid_child (a int) without oids;
+alter table oid_child inherit oid_parent;  -- fail
+alter table oid_child set with oids;
+select attinhcount, attislocal from pg_attribute
+  where attrelid = 'oid_child'::regclass and attname = 'oid';
+alter table oid_child inherit oid_parent;
+select attinhcount, attislocal from pg_attribute
+  where attrelid = 'oid_child'::regclass and attname = 'oid';
+alter table oid_child set without oids;  -- fail
+alter table oid_parent set without oids;
+select attinhcount, attislocal from pg_attribute
+  where attrelid = 'oid_child'::regclass and attname = 'oid';
+alter table oid_child set without oids;
+select attinhcount, attislocal from pg_attribute
+  where attrelid = 'oid_child'::regclass and attname = 'oid';
+
+drop table oid_parent cascade;
+
 -- Test non-inheritable parent constraints
 create table p1(ff1 int);
 alter table p1 add constraint p1chk check (ff1 > 0) no inherit;