Re: Unexpected Standby Shutdown on sync_replication_slots change

Fujii Masao <masao.fujii@gmail.com>

From: Fujii Masao <masao.fujii@gmail.com>

To: Hugo DUBOIS <hdubois@scaleway.com>

Cc: shveta malik <shveta.malik@gmail.com>, pgsql-bugs@lists.postgresql.org

Date: 2025-07-25T16:01:29Z

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 →

Disallow server start with sync_replication_slots = on and wal_level < logical.
- 12da45742cfd 19 (unreleased) landed
Avoid unexpected shutdown when sync_replication_slots is enabled.
- f71fa981c96d 17.6 landed
- 2d81a246f415 18.0 landed
- 4614d53d4ef4 19 (unreleased) landed

Attachments

v2-0001-Avoid-unexpected-shutdown-when-sync_replication_s.patch (application/octet-stream) patch v2-0001

On Fri, Jul 25, 2025 at 9:13 PM Hugo DUBOIS <hdubois@scaleway.com> wrote:
> I'm not sure if there's a particular use case for wal_level and sync_replication_slots not matching on a primary. So, for me, Option 1 seems correct.

I also prefer option #1.

However, on second thought, if some users are already running a server
(non-standby) with sync_replication_slots enabled and wal_level != logical
in v17, switching to option #1 could break their setup after a minor
version update. That would be surprising and confusing.

To avoid that, I think we should go with option #2—at least for v17.

Attached is an updated patch implementing option #2.

Regards,

-- 
Fujii Masao