From: "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>
To: 'Chao Li' <li.evan.chao@gmail.com>
CC: PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: RE: Bug in ALTER SUBSCRIPTION ... SERVER / ... CONNECTION with broken
 old server
Thread-Topic: Bug in ALTER SUBSCRIPTION ... SERVER / ... CONNECTION with
 broken old server
Thread-Index: AQHc0fqtM+kTZUcRL0qAxzAP1hnMFbXq3obQ
Date: Wed, 22 Apr 2026 12:35:02 +0000
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Precedence: bulk

Dear Chao,

> I tested the v19 new feature CREATE SUBSCRIPTION ... SERVER yesterday, an=
d
> found an issue: once the old server becomes broken, the subscription cann=
ot be
> recovered by switching it to a good server.

Thanks for testing. I could reproduce the same issue. In addition to yours,=
 I found
DROP SUBSCRIPTION cannot be done anymore. To switch the connection or drop =
it,
I had to create the same user mapping must be created again.

```
postgres=3D# DROP SUBSCRIPTION sub_bug ;
ERROR:  user mapping not found for user "postgres", server "old_srv"
postgres=3D# CREATE USER MAPPING FOR CURRENT_USER SERVER old_srv
OPTIONS (user 'dummy', password 'dummy');
CREATE USER MAPPING
postgres=3D# DROP SUBSCRIPTION sub_bug ;
DROP SUBSCRIPTION
```

Before deep dive to your fix, I'm unclear why dropping the active USER MAPP=
ING is
allowed. Personally, it should be avoided anyway. Do you know why it's not =
restricted?

Best regards,
Hayato Kuroda
FUJITSU LIMITED