From: Chao Li <li.evan.chao@gmail.com>
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Subject: Fix wrong error message from pg_get_tablespace_ddl()
Message-Id: <53D05145-CE87-424F-A492-BB22A09BBE11@gmail.com>
Date: Fri, 8 May 2026 16:14:40 +0800
To: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
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Hi,

I started testing pg_get_tablespace_ddl(). While tracing =
pg_get_tablespace_ddl_internal(), I noticed that this error report must =
be wrong:
```
	/* User must have SELECT privilege on pg_tablespace. */
	if (pg_class_aclcheck(TableSpaceRelationId, GetUserId(), =
ACL_SELECT) !=3D ACLCHECK_OK)
	{
		ReleaseSysCache(tuple);
		aclcheck_error(ACLCHECK_NO_PRIV, OBJECT_TABLESPACE, =
spcname);
	}
```

The comment clearly says that SELECT privilege on pg_tablespace is =
required, but the error is reported against the target tablespace =
instead.

This is easy to reproduce:
```
evantest=3D# set allow_in_place_tablespaces =3D true;
SET
evantest=3D# create role r1;
CREATE ROLE
evantest=3D# create tablespace ts1 location '';
CREATE TABLESPACE
evantest=3D# revoke select on pg_tablespace from r1;
REVOKE
evantest=3D# set role r1;
SET
evantest=3D> select * from pg_get_tablespace_ddl('ts1');
ERROR:  permission denied for tablespace ts1
```

Attached is a simple one-line fix. Attached is a simple one-line fix. I =
did not add a new test, as we usually try to avoid extending the test =
time for such a small fix. With the fix, the error message now looks =
like:
```
evantest=3D> select * from pg_get_tablespace_ddl('ts1');
ERROR:  permission denied for table pg_tablespace
```

Oops, I was one of the reviewers of the original patch. Sorry for not =
finding this during review.

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/


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Date:=20Fri,=208=20May=202026=2015:53:23=20+0800=0ASubject:=20[PATCH=20=
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