Horton

Re: BUG #18988: DROP SUBSCRIPTION locks not-yet-accessed database

Dilip Kumar <dilipbalaut@gmail.com>

View thread
From: Dilip Kumar <dilipbalaut@gmail.com>
To: "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>
Cc: vignesh C <vignesh21@gmail.com>, "exclusion@gmail.com" <exclusion@gmail.com>, "pgsql-bugs@lists.postgresql.org" <pgsql-bugs@lists.postgresql.org>
Date: 2025-07-31T11:44:01Z
Lists: pgsql-bugs

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Fix self-deadlock during DROP SUBSCRIPTION.

On Thu, Jul 31, 2025 at 2:34 PM Hayato Kuroda (Fujitsu)
<kuroda.hayato@fujitsu.com> wrote:
>
> Dear Vignesh, Dilip,
>
> I found another corner case:
>
> ```
> postgres=# CREATE SUBSCRIPTION sub CONNECTION 'dbname=db1 user=postgres port=5431' PUBLICATION pub1 WITH (connect=false, slot_name=sub);
> WARNING:  subscription was created, but is not connected
> HINT:  To initiate replication, you must manually create the replication slot, enable the subscription, and refresh the subscription.
> CREATE SUBSCRIPTION
> postgres=# DROP SUBSCRIPTION sub ;
> ... (won't return)
> ```
>
> Because still can explicitly specify the slot_name while creating the subscription.
> Another pattern is to run ALTER SUBSCRIPTION SET (slot_name) command after the
> CREATE SUBSCRIPTION WITH (connect=false);.
>
> Should we fix the case? If so, how?

IMHO, what we should do is to set a flag in subscription that whether
the connect is true or not, and drop subscription should not try to
drop the slot if the connect is false, thoughts?

-- 
Regards,
Dilip Kumar
Google