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Re: Exit walsender before confirming remote flush in logical replication

Ronan Dunklau <ronan@dunklau.fr>

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From: Ronan Dunklau <ronan@dunklau.fr>
To: Fujii Masao <masao.fujii@gmail.com>
Cc: Andrey Silitskiy <a.silitskiy@postgrespro.ru>, Vitaly Davydov <v.davydov@postgrespro.ru>, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, "Takamichi Osumi (Fujitsu)" <osumi.takamichi@fujitsu.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>, "sawada.mshk@gmail.com" <sawada.mshk@gmail.com>, "michael@paquier.xyz" <michael@paquier.xyz>, "peter.eisentraut@enterprisedb.com" <peter.eisentraut@enterprisedb.com>, "dilipbalaut@gmail.com" <dilipbalaut@gmail.com>, "andres@anarazel.de" <andres@anarazel.de>, "amit.kapila16@gmail.com" <amit.kapila16@gmail.com>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, Peter Smith <smithpb2250@gmail.com>, Greg Sabino Mullane <htamfids@gmail.com>, Alexander Korotkov <aekorotkov@gmail.com>
Date: 2026-01-28T08:27:28Z
Lists: pgsql-hackers 
On Monday, January 26th, 2026 at 15:08, Fujii Masao <masao.fujii@gmail.com> wrote:
 
> Regarding the GUC name, wal_sender_shutdown seems simple and sufficient to me.
> This isn't a blocker, so I'm fine with the current name for now and
> revisiting it later if needed.

Are we considering other approaches to this ? Having the behavior be either "wait indefinitely" or "terminate immediately" is a bit coarse I think: a timeout for the wait (maybe named wal_sender_stop_timeout ?) would allow for the same usage as this patch provides (set it to -1 for indefinite wait, 0 for immediate shutdown, or any positive value to give a chance to the walsender to catch up before we terminate it forcibly).

The problem we have as of now is when the walreceiver is indeed connected and not reaching wal_sender_timeout as it's still processing: a distinct timeout would alleviate that.

Regards,

--
Ronan Dunklau

Commits

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

  1. Avoid blocking indefinitely while finishing walsender shutdown

  2. Add wal_sender_shutdown_timeout GUC to limit shutdown wait for replication

  3. pg_upgrade: Add --copy option

  4. Prevent possibility of panics during shutdown checkpoint.

  5. Support clean switchover.