v2-0001-Fix-dependencies-under-ALTER-TABLE-SET-ACCESS-MET.patch

From 6ef48042e1eefd30b16438c03e584b41733b3e49 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@paquier.xyz>
Date: Wed, 28 Jun 2023 08:06:31 +0900
Subject: [PATCH v2] Fix dependencies under ALTER TABLE SET ACCESS METHOD

---
 src/backend/commands/cluster.c          | 21 ++++++++++++++++++
 src/test/regress/expected/create_am.out | 29 +++++++++++++++++++++++++
 src/test/regress/sql/create_am.sql      | 18 +++++++++++++++
 3 files changed, 68 insertions(+)

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 3bfabb6d10..e84460a43e 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -1070,6 +1070,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
 				relfilenumber2;
 	RelFileNumber swaptemp;
 	char		swptmpchr;
+	Oid			relam1,
+				relam2;
 
 	/* We need writable copies of both pg_class tuples. */
 	relRelation = table_open(RelationRelationId, RowExclusiveLock);
@@ -1086,6 +1088,8 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
 
 	relfilenumber1 = relform1->relfilenode;
 	relfilenumber2 = relform2->relfilenode;
+	relam1 = relform1->relam;
+	relam2 = relform2->relam;
 
 	if (RelFileNumberIsValid(relfilenumber1) &&
 		RelFileNumberIsValid(relfilenumber2))
@@ -1257,6 +1261,23 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
 		CacheInvalidateRelcacheByTuple(reltup2);
 	}
 
+	/*
+	 * Now that pg_class has been updated with its relevant information for
+	 * the swap, update the dependency of the relation to point to its new
+	 * table AM, if it has changed.
+	 */
+	if (relam1 != relam2)
+	{
+		if (changeDependencyFor(RelationRelationId,
+								r1,
+								AccessMethodRelationId,
+								relam1,
+								relam2) != 1)
+			elog(ERROR, "failed to change access method dependency for relation \"%s.%s\"",
+				 get_namespace_name(get_rel_namespace(r1)),
+				 get_rel_name(r1));
+	}
+
 	/*
 	 * Post alter hook for modified relations. The change to r2 is always
 	 * internal, but r1 depends on the invocation context.
diff --git a/src/test/regress/expected/create_am.out b/src/test/regress/expected/create_am.out
index e9a9283d7a..4eec292e65 100644
--- a/src/test/regress/expected/create_am.out
+++ b/src/test/regress/expected/create_am.out
@@ -240,6 +240,35 @@ SELECT amname FROM pg_class c, pg_am am
  heap
 (1 row)
 
+-- Switching to heap2 adds new dependency entry to the AM.
+ALTER TABLE heaptable SET ACCESS METHOD heap2;
+SELECT pg_describe_object(classid, objid, objsubid) as obj,
+       pg_describe_object(refclassid,refobjid,refobjsubid) as objref,
+       deptype
+  FROM pg_depend
+  WHERE classid = 'pg_class'::regclass AND
+        objid = 'heaptable'::regclass
+  ORDER BY 1, 2;
+       obj       |       objref        | deptype 
+-----------------+---------------------+---------
+ table heaptable | access method heap2 | n
+ table heaptable | schema public       | n
+(2 rows)
+
+-- Switching to heap should not have a dependency entry to the AM.
+ALTER TABLE heaptable SET ACCESS METHOD heap;
+SELECT pg_describe_object(classid, objid, objsubid) as obj,
+       pg_describe_object(refclassid,refobjid,refobjsubid) as objref,
+       deptype
+  FROM pg_depend
+  WHERE classid = 'pg_class'::regclass AND
+        objid = 'heaptable'::regclass
+  ORDER BY 1, 2;
+       obj       |    objref     | deptype 
+-----------------+---------------+---------
+ table heaptable | schema public | n
+(1 row)
+
 ALTER TABLE heaptable SET ACCESS METHOD heap2;
 SELECT amname FROM pg_class c, pg_am am
   WHERE c.relam = am.oid AND c.oid = 'heaptable'::regclass;
diff --git a/src/test/regress/sql/create_am.sql b/src/test/regress/sql/create_am.sql
index 256884c959..f1c809b8e0 100644
--- a/src/test/regress/sql/create_am.sql
+++ b/src/test/regress/sql/create_am.sql
@@ -166,6 +166,24 @@ CREATE TABLE heaptable USING heap AS
   SELECT a, repeat(a::text, 100) FROM generate_series(1,9) AS a;
 SELECT amname FROM pg_class c, pg_am am
   WHERE c.relam = am.oid AND c.oid = 'heaptable'::regclass;
+-- Switching to heap2 adds new dependency entry to the AM.
+ALTER TABLE heaptable SET ACCESS METHOD heap2;
+SELECT pg_describe_object(classid, objid, objsubid) as obj,
+       pg_describe_object(refclassid,refobjid,refobjsubid) as objref,
+       deptype
+  FROM pg_depend
+  WHERE classid = 'pg_class'::regclass AND
+        objid = 'heaptable'::regclass
+  ORDER BY 1, 2;
+-- Switching to heap should not have a dependency entry to the AM.
+ALTER TABLE heaptable SET ACCESS METHOD heap;
+SELECT pg_describe_object(classid, objid, objsubid) as obj,
+       pg_describe_object(refclassid,refobjid,refobjsubid) as objref,
+       deptype
+  FROM pg_depend
+  WHERE classid = 'pg_class'::regclass AND
+        objid = 'heaptable'::regclass
+  ORDER BY 1, 2;
 ALTER TABLE heaptable SET ACCESS METHOD heap2;
 SELECT amname FROM pg_class c, pg_am am
   WHERE c.relam = am.oid AND c.oid = 'heaptable'::regclass;
-- 
2.40.1