Hi,
On Wed, Apr 24, 2024 at 03:00:00PM +0300, Alexander Lakhin wrote:
> 24.04.2024 11:38, Bertrand Drouvot wrote:
> > I gave more thought to v2 and the approach seems reasonable to me.
> > Basically what
> > it does is that in case the object is already dropped before we take the
> > new lock
> > (while recording the dependency) then the error message is a "generic" one
> > (means
> > it does not provide the description of the "already" dropped object). I
> > think it
> > makes sense to write the patch that way by abandoning the patch's ambition
> > to
> > tell the description of the dropped object in all the cases.
> >
> > Of course, I would be happy to hear others thought about it.
> >
> > Please find v3 attached (which is v2 with more comments).
>
> Thank you for the improved version!
>
> I can confirm that it fixes that case.
Great, thanks for the test!
> I've also tested other cases that fail on master (most of them also fail
> with v1), please try/look at the attached script.
Thanks for all those tests!
> (There could be other broken-dependency cases, of course, but I think I've
> covered all the representative ones.)
Agree. Furthermore the way the patch is written should be agnostic to the
object's kind that are part of the dependency. Having said that, that does not
hurt to add more tests in this patch, so v4 attached adds some of your tests (
that would fail on the master branch without the patch applied).
The way the tests are written in the patch are less "racy" that when triggered
with your script. Indeed, I think that in the patch the dependent object can not
be removed before the new lock is taken when recording the dependency. We may
want to add injection points in the game if we feel the need.
> All tested cases work correctly with v3 applied —
Yeah, same on my side, I did run them too and did not find any issues.
> I couldn't get broken
> dependencies,
Same here.
> though concurrent create/drop operations can still produce
> the "cache lookup failed" error, which is probably okay, except that it is
> an INTERNAL_ERROR, which assumed to be not easily triggered by users.
I did not see any of those "cache lookup failed" during my testing with/without
your script. During which test(s) did you see those with v3 applied?
Attached v4, simply adding more tests to v3.
Regards,
--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com
>From a9b34955fab0351b7b5a7ba6eb36f199f5a5822c Mon Sep 17 00:00:00 2001
From: Bertrand Drouvot <bertranddrouvot...@gmail.com>
Date: Fri, 29 Mar 2024 15:43:26 +0000
Subject: [PATCH v4] Avoid orphaned objects dependencies
It's currently possible to create orphaned objects dependencies, for example:
Scenario 1:
session 1: begin; drop schema schem;
session 2: create a function in the schema schem
session 1: commit;
With the above, the function created in session 2 would be linked to a non
existing schema.
Scenario 2:
session 1: begin; create a function in the schema schem
session 2: drop schema schem;
session 1: commit;
With the above, the function created in session 1 would be linked to a non
existing schema.
To avoid those scenarios, a new lock (that conflicts with a lock taken by DROP)
has been put in place when the dependencies are being recorded. With this in
place, the drop schema in scenario 2 would be locked.
Also, after the new lock attempt, the patch checks that the object still exists:
with this in place session 2 in scenario 1 would be locked and would report an
error once session 1 committs (that would not be the case should session 1 abort
the transaction).
If the object is dropped before the new lock attempt is triggered then the patch
would also report an error (but with less details).
The patch adds a few tests for some dependency cases (that would currently produce
orphaned objects):
- schema and function (as the above scenarios)
- function and arg type
- function and return type
- function and function
- domain and domain
- table and type
- server and foreign data wrapper
---
src/backend/catalog/dependency.c | 54 +++++++++
src/backend/catalog/objectaddress.c | 70 +++++++++++
src/backend/catalog/pg_depend.c | 6 +
src/include/catalog/dependency.h | 1 +
src/include/catalog/objectaddress.h | 1 +
src/test/modules/Makefile | 1 +
src/test/modules/meson.build | 1 +
.../test_dependencies_locks/.gitignore | 3 +
.../modules/test_dependencies_locks/Makefile | 14 +++
.../expected/test_dependencies_locks.out | 113 ++++++++++++++++++
.../test_dependencies_locks/meson.build | 12 ++
.../specs/test_dependencies_locks.spec | 78 ++++++++++++
12 files changed, 354 insertions(+)
24.6% src/backend/catalog/
42.7% src/test/modules/test_dependencies_locks/expected/
25.9% src/test/modules/test_dependencies_locks/specs/
5.0% src/test/modules/test_dependencies_locks/
diff --git a/src/backend/catalog/dependency.c b/src/backend/catalog/dependency.c
index d4b5b2ade1..a49357bbe2 100644
--- a/src/backend/catalog/dependency.c
+++ b/src/backend/catalog/dependency.c
@@ -1517,6 +1517,60 @@ AcquireDeletionLock(const ObjectAddress *object, int flags)
}
}
+/*
+ * depLockAndCheckObject
+ *
+ * Lock the object that we are about to record a dependency on.
+ * After it's locked, verify that it hasn't been dropped while we
+ * weren't looking. If the object has been dropped, this function
+ * does not return!
+ */
+void
+depLockAndCheckObject(const ObjectAddress *object)
+{
+ char *object_description;
+
+ /*
+ * Those don't rely on LockDatabaseObject() when being dropped (see
+ * AcquireDeletionLock()). Also it looks like they can not produce
+ * orphaned dependent objects when being dropped.
+ */
+ if (object->classId == RelationRelationId || object->classId == AuthMemRelationId)
+ return;
+
+ object_description = getObjectDescription(object, true);
+
+ /* assume we should lock the whole object not a sub-object */
+ LockDatabaseObject(object->classId, object->objectId, 0, AccessShareLock);
+
+ /* check if object still exists */
+ if (!ObjectByIdExist(object, false))
+ {
+ /*
+ * It might be possible that we are creating it (for example creating
+ * a composite type while creating a relation), so bypass the syscache
+ * lookup and use a dirty snaphot instead to cover this scenario.
+ */
+ if (!ObjectByIdExist(object, true))
+ {
+ /*
+ * If the object has been dropped before we get a chance to get
+ * its description, then emit a generic error message. That looks
+ * like a good compromise over extra complexity.
+ */
+ if (object_description)
+ ereport(ERROR, errmsg("%s does not exist", object_description));
+ else
+ ereport(ERROR, errmsg("a dependent object does not exist"));
+ }
+ }
+
+ if (object_description)
+ pfree(object_description);
+
+ return;
+}
+
/*
* ReleaseDeletionLock - release an object deletion lock
*
diff --git a/src/backend/catalog/objectaddress.c b/src/backend/catalog/objectaddress.c
index 7b536ac6fd..c2b873dd81 100644
--- a/src/backend/catalog/objectaddress.c
+++ b/src/backend/catalog/objectaddress.c
@@ -2590,6 +2590,76 @@ get_object_namespace(const ObjectAddress *address)
return oid;
}
+/*
+ * ObjectByIdExist
+ *
+ * Return whether the given object exists.
+ *
+ * Works for most catalogs, if no special processing is needed.
+ */
+bool
+ObjectByIdExist(const ObjectAddress *address, bool use_dirty_snapshot)
+{
+ HeapTuple tuple;
+ int cache = -1;
+ const ObjectPropertyType *property;
+
+ if (!use_dirty_snapshot)
+ {
+ property = get_object_property_data(address->classId);
+
+ cache = property->oid_catcache_id;
+ }
+
+ if (cache >= 0)
+ {
+ /* Fetch tuple from syscache. */
+ tuple = SearchSysCache1(cache, ObjectIdGetDatum(address->objectId));
+
+ if (!HeapTupleIsValid(tuple))
+ {
+ return false;
+ }
+
+ ReleaseSysCache(tuple);
+
+ return true;
+ }
+ else
+ {
+ Relation rel;
+ ScanKeyData skey[1];
+ SysScanDesc scan;
+ SnapshotData DirtySnapshot;
+ Snapshot snapshot;
+
+ if (use_dirty_snapshot)
+ {
+ InitDirtySnapshot(DirtySnapshot);
+ snapshot = &DirtySnapshot;
+ }
+ else
+ snapshot = NULL;
+
+ rel = table_open(address->classId, AccessShareLock);
+
+ ScanKeyInit(&skey[0],
+ get_object_attnum_oid(address->classId),
+ BTEqualStrategyNumber, F_OIDEQ,
+ ObjectIdGetDatum(address->objectId));
+
+ scan = systable_beginscan(rel, get_object_oid_index(address->classId), true,
+ snapshot, 1, skey);
+
+ /* we expect exactly one match */
+ tuple = systable_getnext(scan);
+ systable_endscan(scan);
+ table_close(rel, AccessShareLock);
+
+ return (HeapTupleIsValid(tuple));
+ }
+}
+
/*
* Return ObjectType for the given object type as given by
* getObjectTypeDescription; if no valid ObjectType code exists, but it's a
diff --git a/src/backend/catalog/pg_depend.c b/src/backend/catalog/pg_depend.c
index f85a898de8..6bb218f5dd 100644
--- a/src/backend/catalog/pg_depend.c
+++ b/src/backend/catalog/pg_depend.c
@@ -106,6 +106,12 @@ recordMultipleDependencies(const ObjectAddress *depender,
if (isObjectPinned(referenced))
continue;
+ /*
+ * Acquire a lock and check object still exists while recording the
+ * dependency. XXX - Should we do so only for DEPENDENCY_NORMAL?
+ */
+ depLockAndCheckObject(referenced);
+
if (slot_init_count < max_slots)
{
slot[slot_stored_count] = MakeSingleTupleTableSlot(RelationGetDescr(dependDesc),
diff --git a/src/include/catalog/dependency.h b/src/include/catalog/dependency.h
index ec654010d4..8915548711 100644
--- a/src/include/catalog/dependency.h
+++ b/src/include/catalog/dependency.h
@@ -94,6 +94,7 @@ typedef struct ObjectAddresses ObjectAddresses;
/* in dependency.c */
extern void AcquireDeletionLock(const ObjectAddress *object, int flags);
+extern void depLockAndCheckObject(const ObjectAddress *object);
extern void ReleaseDeletionLock(const ObjectAddress *object);
diff --git a/src/include/catalog/objectaddress.h b/src/include/catalog/objectaddress.h
index 3a70d80e32..04891abcc1 100644
--- a/src/include/catalog/objectaddress.h
+++ b/src/include/catalog/objectaddress.h
@@ -53,6 +53,7 @@ extern void check_object_ownership(Oid roleid,
Node *object, Relation relation);
extern Oid get_object_namespace(const ObjectAddress *address);
+extern bool ObjectByIdExist(const ObjectAddress *address, bool use_dirty_snapshot);
extern bool is_objectclass_supported(Oid class_id);
extern const char *get_object_class_descr(Oid class_id);
diff --git a/src/test/modules/Makefile b/src/test/modules/Makefile
index 256799f520..75f357100f 100644
--- a/src/test/modules/Makefile
+++ b/src/test/modules/Makefile
@@ -17,6 +17,7 @@ SUBDIRS = \
test_copy_callbacks \
test_custom_rmgrs \
test_ddl_deparse \
+ test_dependencies_locks \
test_dsa \
test_dsm_registry \
test_extensions \
diff --git a/src/test/modules/meson.build b/src/test/modules/meson.build
index d8fe059d23..60305dcccd 100644
--- a/src/test/modules/meson.build
+++ b/src/test/modules/meson.build
@@ -16,6 +16,7 @@ subdir('test_bloomfilter')
subdir('test_copy_callbacks')
subdir('test_custom_rmgrs')
subdir('test_ddl_deparse')
+subdir('test_dependencies_locks')
subdir('test_dsa')
subdir('test_dsm_registry')
subdir('test_extensions')
diff --git a/src/test/modules/test_dependencies_locks/.gitignore b/src/test/modules/test_dependencies_locks/.gitignore
new file mode 100644
index 0000000000..bf000faac4
--- /dev/null
+++ b/src/test/modules/test_dependencies_locks/.gitignore
@@ -0,0 +1,3 @@
+# Generated subdirectories
+/log/
+/output_iso
diff --git a/src/test/modules/test_dependencies_locks/Makefile b/src/test/modules/test_dependencies_locks/Makefile
new file mode 100644
index 0000000000..7491048380
--- /dev/null
+++ b/src/test/modules/test_dependencies_locks/Makefile
@@ -0,0 +1,14 @@
+# src/test/modules/test_dependencies_locks/Makefile
+
+ISOLATION = test_dependencies_locks
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = src/test/modules/test_dependencies_locks
+top_builddir = ../../../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/src/test/modules/test_dependencies_locks/expected/test_dependencies_locks.out b/src/test/modules/test_dependencies_locks/expected/test_dependencies_locks.out
new file mode 100644
index 0000000000..93318c9cbb
--- /dev/null
+++ b/src/test/modules/test_dependencies_locks/expected/test_dependencies_locks.out
@@ -0,0 +1,113 @@
+Parsed test spec with 2 sessions
+
+starting permutation: s1_begin s1_create_function_in_schema s2_drop_schema s1_commit
+step s1_begin: BEGIN;
+step s1_create_function_in_schema: CREATE FUNCTION testschema.foo() RETURNS int AS 'select 1' LANGUAGE sql;
+step s2_drop_schema: DROP SCHEMA testschema; <waiting ...>
+step s1_commit: COMMIT;
+step s2_drop_schema: <... completed>
+ERROR: cannot drop schema testschema because other objects depend on it
+
+starting permutation: s2_begin s2_drop_schema s1_create_function_in_schema s2_commit
+step s2_begin: BEGIN;
+step s2_drop_schema: DROP SCHEMA testschema;
+step s1_create_function_in_schema: CREATE FUNCTION testschema.foo() RETURNS int AS 'select 1' LANGUAGE sql; <waiting ...>
+step s2_commit: COMMIT;
+step s1_create_function_in_schema: <... completed>
+ERROR: schema testschema does not exist
+
+starting permutation: s1_begin s1_create_function_with_argtype s2_drop_foo_type s1_commit
+step s1_begin: BEGIN;
+step s1_create_function_with_argtype: CREATE FUNCTION fooargtype(num foo) RETURNS int AS 'select 1' LANGUAGE sql;
+step s2_drop_foo_type: DROP TYPE public.foo; <waiting ...>
+step s1_commit: COMMIT;
+step s2_drop_foo_type: <... completed>
+ERROR: cannot drop type foo because other objects depend on it
+
+starting permutation: s2_begin s2_drop_foo_type s1_create_function_with_argtype s2_commit
+step s2_begin: BEGIN;
+step s2_drop_foo_type: DROP TYPE public.foo;
+step s1_create_function_with_argtype: CREATE FUNCTION fooargtype(num foo) RETURNS int AS 'select 1' LANGUAGE sql; <waiting ...>
+step s2_commit: COMMIT;
+step s1_create_function_with_argtype: <... completed>
+ERROR: type foo does not exist
+
+starting permutation: s1_begin s1_create_function_with_rettype s2_drop_foo_rettype s1_commit
+step s1_begin: BEGIN;
+step s1_create_function_with_rettype: CREATE FUNCTION footrettype() RETURNS id LANGUAGE sql RETURN 1;
+step s2_drop_foo_rettype: DROP DOMAIN id; <waiting ...>
+step s1_commit: COMMIT;
+step s2_drop_foo_rettype: <... completed>
+ERROR: cannot drop type id because other objects depend on it
+
+starting permutation: s2_begin s2_drop_foo_rettype s1_create_function_with_rettype s2_commit
+step s2_begin: BEGIN;
+step s2_drop_foo_rettype: DROP DOMAIN id;
+step s1_create_function_with_rettype: CREATE FUNCTION footrettype() RETURNS id LANGUAGE sql RETURN 1; <waiting ...>
+step s2_commit: COMMIT;
+step s1_create_function_with_rettype: <... completed>
+ERROR: type id does not exist
+
+starting permutation: s1_begin s1_create_function_with_function s2_drop_function_f s1_commit
+step s1_begin: BEGIN;
+step s1_create_function_with_function: CREATE FUNCTION foofunc() RETURNS int LANGUAGE SQL RETURN f() + 1;
+step s2_drop_function_f: DROP FUNCTION f(); <waiting ...>
+step s1_commit: COMMIT;
+step s2_drop_function_f: <... completed>
+ERROR: cannot drop function f() because other objects depend on it
+
+starting permutation: s2_begin s2_drop_function_f s1_create_function_with_function s2_commit
+step s2_begin: BEGIN;
+step s2_drop_function_f: DROP FUNCTION f();
+step s1_create_function_with_function: CREATE FUNCTION foofunc() RETURNS int LANGUAGE SQL RETURN f() + 1; <waiting ...>
+step s2_commit: COMMIT;
+step s1_create_function_with_function: <... completed>
+ERROR: function f() does not exist
+
+starting permutation: s1_begin s1_create_domain_with_domain s2_drop_domain_id s1_commit
+step s1_begin: BEGIN;
+step s1_create_domain_with_domain: CREATE DOMAIN idid as id;
+step s2_drop_domain_id: DROP DOMAIN id; <waiting ...>
+step s1_commit: COMMIT;
+step s2_drop_domain_id: <... completed>
+ERROR: cannot drop type id because other objects depend on it
+
+starting permutation: s2_begin s2_drop_domain_id s1_create_domain_with_domain s2_commit
+step s2_begin: BEGIN;
+step s2_drop_domain_id: DROP DOMAIN id;
+step s1_create_domain_with_domain: CREATE DOMAIN idid as id; <waiting ...>
+step s2_commit: COMMIT;
+step s1_create_domain_with_domain: <... completed>
+ERROR: type id does not exist
+
+starting permutation: s1_begin s1_create_table_with_type s2_drop_footab_type s1_commit
+step s1_begin: BEGIN;
+step s1_create_table_with_type: CREATE TABLE tabtype(a footab);
+step s2_drop_footab_type: DROP TYPE public.footab; <waiting ...>
+step s1_commit: COMMIT;
+step s2_drop_footab_type: <... completed>
+ERROR: cannot drop type footab because other objects depend on it
+
+starting permutation: s2_begin s2_drop_footab_type s1_create_table_with_type s2_commit
+step s2_begin: BEGIN;
+step s2_drop_footab_type: DROP TYPE public.footab;
+step s1_create_table_with_type: CREATE TABLE tabtype(a footab); <waiting ...>
+step s2_commit: COMMIT;
+step s1_create_table_with_type: <... completed>
+ERROR: type footab does not exist
+
+starting permutation: s1_begin s1_create_server_with_fdw_wrapper s2_drop_fdw_wrapper s1_commit
+step s1_begin: BEGIN;
+step s1_create_server_with_fdw_wrapper: CREATE SERVER srv_fdw_wrapper FOREIGN DATA WRAPPER fdw_wrapper;
+step s2_drop_fdw_wrapper: DROP FOREIGN DATA WRAPPER fdw_wrapper RESTRICT; <waiting ...>
+step s1_commit: COMMIT;
+step s2_drop_fdw_wrapper: <... completed>
+ERROR: cannot drop foreign-data wrapper fdw_wrapper because other objects depend on it
+
+starting permutation: s2_begin s2_drop_fdw_wrapper s1_create_server_with_fdw_wrapper s2_commit
+step s2_begin: BEGIN;
+step s2_drop_fdw_wrapper: DROP FOREIGN DATA WRAPPER fdw_wrapper RESTRICT;
+step s1_create_server_with_fdw_wrapper: CREATE SERVER srv_fdw_wrapper FOREIGN DATA WRAPPER fdw_wrapper; <waiting ...>
+step s2_commit: COMMIT;
+step s1_create_server_with_fdw_wrapper: <... completed>
+ERROR: foreign-data wrapper fdw_wrapper does not exist
diff --git a/src/test/modules/test_dependencies_locks/meson.build b/src/test/modules/test_dependencies_locks/meson.build
new file mode 100644
index 0000000000..92a978ab93
--- /dev/null
+++ b/src/test/modules/test_dependencies_locks/meson.build
@@ -0,0 +1,12 @@
+# Copyright (c) 2024, PostgreSQL Global Development Group
+
+tests += {
+ 'name': 'test_dependencies_locks',
+ 'sd': meson.current_source_dir(),
+ 'bd': meson.current_build_dir(),
+ 'isolation': {
+ 'specs': [
+ 'test_dependencies_locks',
+ ],
+ },
+}
diff --git a/src/test/modules/test_dependencies_locks/specs/test_dependencies_locks.spec b/src/test/modules/test_dependencies_locks/specs/test_dependencies_locks.spec
new file mode 100644
index 0000000000..3d90a29c47
--- /dev/null
+++ b/src/test/modules/test_dependencies_locks/specs/test_dependencies_locks.spec
@@ -0,0 +1,78 @@
+setup
+{
+ CREATE SCHEMA testschema;
+ CREATE TYPE public.foo as enum ('one', 'two');
+ CREATE TYPE public.footab as enum ('three', 'four');
+ CREATE DOMAIN id AS int;
+ CREATE FUNCTION f() RETURNS int LANGUAGE SQL RETURN 1;
+ CREATE FOREIGN DATA WRAPPER fdw_wrapper;
+}
+
+teardown
+{
+ DROP FUNCTION IF EXISTS testschema.foo();
+ DROP FUNCTION IF EXISTS fooargtype(num foo);
+ DROP FUNCTION IF EXISTS footrettype();
+ DROP FUNCTION IF EXISTS foofunc();
+ DROP DOMAIN IF EXISTS idid;
+ DROP SERVER IF EXISTS srv_fdw_wrapper;
+ DROP TABLE IF EXISTS tabtype;
+ DROP SCHEMA IF EXISTS testschema;
+ DROP TYPE IF EXISTS public.foo;
+ DROP TYPE IF EXISTS public.footab;
+ DROP DOMAIN IF EXISTS id;
+ DROP FUNCTION IF EXISTS f();
+ DROP FOREIGN DATA WRAPPER IF EXISTS fdw_wrapper;
+}
+
+session "s1"
+
+step "s1_begin" { BEGIN; }
+step "s1_create_function_in_schema" { CREATE FUNCTION testschema.foo() RETURNS int AS 'select 1' LANGUAGE sql; }
+step "s1_create_function_with_argtype" { CREATE FUNCTION fooargtype(num foo) RETURNS int AS 'select 1' LANGUAGE sql; }
+step "s1_create_function_with_rettype" { CREATE FUNCTION footrettype() RETURNS id LANGUAGE sql RETURN 1; }
+step "s1_create_function_with_function" { CREATE FUNCTION foofunc() RETURNS int LANGUAGE SQL RETURN f() + 1; }
+step "s1_create_domain_with_domain" { CREATE DOMAIN idid as id; }
+step "s1_create_table_with_type" { CREATE TABLE tabtype(a footab); }
+step "s1_create_server_with_fdw_wrapper" { CREATE SERVER srv_fdw_wrapper FOREIGN DATA WRAPPER fdw_wrapper; }
+step "s1_commit" { COMMIT; }
+
+session "s2"
+
+step "s2_begin" { BEGIN; }
+step "s2_drop_schema" { DROP SCHEMA testschema; }
+step "s2_drop_foo_type" { DROP TYPE public.foo; }
+step "s2_drop_foo_rettype" { DROP DOMAIN id; }
+step "s2_drop_footab_type" { DROP TYPE public.footab; }
+step "s2_drop_function_f" { DROP FUNCTION f(); }
+step "s2_drop_domain_id" { DROP DOMAIN id; }
+step "s2_drop_fdw_wrapper" { DROP FOREIGN DATA WRAPPER fdw_wrapper RESTRICT; }
+step "s2_commit" { COMMIT; }
+
+# function - schema
+permutation "s1_begin" "s1_create_function_in_schema" "s2_drop_schema" "s1_commit"
+permutation "s2_begin" "s2_drop_schema" "s1_create_function_in_schema" "s2_commit"
+
+# function - argtype
+permutation "s1_begin" "s1_create_function_with_argtype" "s2_drop_foo_type" "s1_commit"
+permutation "s2_begin" "s2_drop_foo_type" "s1_create_function_with_argtype" "s2_commit"
+
+# function - rettype
+permutation "s1_begin" "s1_create_function_with_rettype" "s2_drop_foo_rettype" "s1_commit"
+permutation "s2_begin" "s2_drop_foo_rettype" "s1_create_function_with_rettype" "s2_commit"
+
+# function - function
+permutation "s1_begin" "s1_create_function_with_function" "s2_drop_function_f" "s1_commit"
+permutation "s2_begin" "s2_drop_function_f" "s1_create_function_with_function" "s2_commit"
+
+# domain - domain
+permutation "s1_begin" "s1_create_domain_with_domain" "s2_drop_domain_id" "s1_commit"
+permutation "s2_begin" "s2_drop_domain_id" "s1_create_domain_with_domain" "s2_commit"
+
+# table - type
+permutation "s1_begin" "s1_create_table_with_type" "s2_drop_footab_type" "s1_commit"
+permutation "s2_begin" "s2_drop_footab_type" "s1_create_table_with_type" "s2_commit"
+
+# server - foreign data wrapper
+permutation "s1_begin" "s1_create_server_with_fdw_wrapper" "s2_drop_fdw_wrapper" "s1_commit"
+permutation "s2_begin" "s2_drop_fdw_wrapper" "s1_create_server_with_fdw_wrapper" "s2_commit"
--
2.34.1
