BUG #18912: TRAP: failed Assert("tag.spcOid != GLOBALTABLESPACE_OID"), File: "bufmgr.c", Line: 4165, PID: 2115
The following bug has been logged on the website:
Bug reference: 18912
Logged by: Adam Guo
Email address: adamguo@amazon.com
PostgreSQL version: Unsupported/Unknown
Operating system: Amazon Linux 2
Description:
Hi team,
I noticed an assert failure in PG18beta1. I can reproduce it by running the
following:
```
CREATE USER myuser;
REINDEX SCHEMA pg_catalog;
SET SESSION AUTHORIZATION myuser;
GRANT ALTER SYSTEM ON PARAMETER log_filename TO myuser;
GRANT ALTER SYSTEM ON PARAMETER log_filename TO myuser WITH GRANT OPTION;
```
From what I can tell, all of these statements are necessary to reproduce the
error. On the last one, the backend aborts at buffer/bufmgr.c:4165 [1]https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/backend/storage/buffer/bufmgr.c;hb=HEAD#l4165.
This
assert was introduced in f4ece891 [2]https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=f4ece891fc2f. Seems like something is holding onto
an
LW_EXCLUSIVE lock on a system catalog?
According to gdb, the relation in question is not a system catalog but does
live
in the pg_global tablespace. I can't find it in pg_class.
```
(gdb) up 3
#3 0x00000000009e1f48 in AssertNotCatalogBufferLock (lock=0x7f8ab5782c30,
mode=LW_EXCLUSIVE,
unused_context=0x0) at bufmgr.c:4165
4165 Assert(tag.spcOid != GLOBALTABLESPACE_OID);
(gdb) p tag.spcOid
$1 = 1664
(gdb) p relid
$2 = 16526
```
Regards,
Adam Guo
[1]: https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/backend/storage/buffer/bufmgr.c;hb=HEAD#l4165
https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/backend/storage/buffer/bufmgr.c;hb=HEAD#l4165
[2]: https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=f4ece891fc2f
https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=f4ece891fc2f
On Mon, May 05, 2025 at 10:01:15PM +0000, PG Bug reporting form wrote:
```
CREATE USER myuser;
REINDEX SCHEMA pg_catalog;
SET SESSION AUTHORIZATION myuser;
GRANT ALTER SYSTEM ON PARAMETER log_filename TO myuser;
GRANT ALTER SYSTEM ON PARAMETER log_filename TO myuser WITH GRANT OPTION;
```
From what I can tell, all of these statements are necessary to reproduce the
error. On the last one, the backend aborts at buffer/bufmgr.c:4165 [1].
This
assert was introduced in f4ece891 [2]. Seems like something is holding onto
an
LW_EXCLUSIVE lock on a system catalog?
According to gdb, the relation in question is not a system catalog but does
live
in the pg_global tablespace. I can't find it in pg_class.
```
(gdb) up 3
#3 0x00000000009e1f48 in AssertNotCatalogBufferLock (lock=0x7f8ab5782c30,
mode=LW_EXCLUSIVE,
unused_context=0x0) at bufmgr.c:4165
4165 Assert(tag.spcOid != GLOBALTABLESPACE_OID);
(gdb) p tag.spcOid
$1 = 1664
(gdb) p relid
$2 = 16526
```
Thanks for the report. On my system, it's pg_parameter_acl_parname_index:
[local] test=*# select pg_filenode_relation(1664, '16529');
pg_filenode_relation
────────────────────────────────
pg_parameter_acl_parname_index
(1 row)
That's an IsCatalogTextUniqueIndexOid() index, but the REINDEX makes
AssertNotCatalogBufferLock() unable to detect it as one. Hence, I think I'll
be removing the assert you reached:
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -4160,10 +4160,8 @@ AssertNotCatalogBufferLock(LWLock *lock, LWLockMode mode,
if (IsCatalogTextUniqueIndexOid(relid)) /* see comments at the callee */
return; Assert(!IsCatalogRelationOid(relid));
- /* Shared rels are always catalogs: detect even after VACUUM FULL. */
- Assert(tag.spcOid != GLOBALTABLESPACE_OID);
}
It's true that shared rels are always catalogs. However, without a way to
judge IsCatalogTextUniqueIndexOid(), we can't assert-fail.
On Mon, May 5, 2025 at 5:31 PM Noah Misch <noah@leadboat.com> wrote:
On Mon, May 05, 2025 at 10:01:15PM +0000, PG Bug reporting form wrote:
```
CREATE USER myuser;
REINDEX SCHEMA pg_catalog;
SET SESSION AUTHORIZATION myuser;
GRANT ALTER SYSTEM ON PARAMETER log_filename TO myuser;
GRANT ALTER SYSTEM ON PARAMETER log_filename TO myuser WITH GRANT OPTION;
```
From what I can tell, all of these statements are necessary to reproduce the
error. On the last one, the backend aborts at buffer/bufmgr.c:4165 [1].
This
assert was introduced in f4ece891 [2]. Seems like something is holding onto
an
LW_EXCLUSIVE lock on a system catalog?
According to gdb, the relation in question is not a system catalog but does
live
in the pg_global tablespace. I can't find it in pg_class.
```
(gdb) up 3
#3 0x00000000009e1f48 in AssertNotCatalogBufferLock (lock=0x7f8ab5782c30,
mode=LW_EXCLUSIVE,
unused_context=0x0) at bufmgr.c:4165
4165 Assert(tag.spcOid != GLOBALTABLESPACE_OID);
(gdb) p tag.spcOid
$1 = 1664
(gdb) p relid
$2 = 16526
```Thanks for the report. On my system, it's pg_parameter_acl_parname_index:
[local] test=*# select pg_filenode_relation(1664, '16529');
pg_filenode_relation
────────────────────────────────
pg_parameter_acl_parname_index
(1 row)That's an IsCatalogTextUniqueIndexOid() index, but the REINDEX makes
AssertNotCatalogBufferLock() unable to detect it as one. Hence, I think I'll
be removing the assert you reached:--- a/src/backend/storage/buffer/bufmgr.c +++ b/src/backend/storage/buffer/bufmgr.c @@ -4160,10 +4160,8 @@ AssertNotCatalogBufferLock(LWLock *lock, LWLockMode mode, if (IsCatalogTextUniqueIndexOid(relid)) /* see comments at the callee */ return;Assert(!IsCatalogRelationOid(relid));
- /* Shared rels are always catalogs: detect even after VACUUM FULL. */
- Assert(tag.spcOid != GLOBALTABLESPACE_OID);
}
+1. Seems reasonable approach.
Regards,
--
Masahiko Sawada
Amazon Web Services: https://aws.amazon.com