Re: Implement waiting for wal lsn replay: reloaded

Alexander Korotkov <aekorotkov@gmail.com>

From: Alexander Korotkov <aekorotkov@gmail.com>

To: Andres Freund <andres@anarazel.de>

Cc: Álvaro Herrera <alvherre@kurilemu.de>, Xuneng Zhou <xunengzhou@gmail.com>, pgsql-hackers <pgsql-hackers@lists.postgresql.org>, Michael Paquier <michael@paquier.xyz>, jian he <jian.universality@gmail.com>, Tomas Vondra <tomas@vondra.me>, Yura Sokolov <y.sokolov@postgrespro.ru>

Date: 2025-11-05T09:51:18Z

Lists: pgsql-hackers

Commits

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

Clean up 019_replslot_limit.pl comments
- 0b866bb90368 19 (unreleased) landed
Stabilize 019_replslot_limit.pl: wait on slot restart_lsn
- cdb1d1cf1de6 19 (unreleased) landed
Use WAIT FOR LSN in PostgreSQL::Test::Cluster::wait_for_catchup()
- 7e8aeb9e483d 19 (unreleased) landed
- f30848cb05d4 19 (unreleased) landed
Add tab completion for the WAIT FOR LSN MODE option
- 76948337f724 19 (unreleased) landed
Add the MODE option to the WAIT FOR LSN command
- 49a181b5d634 19 (unreleased) landed
Extend xlogwait infrastructure with write and flush wait types
- 7a39f43d885b 19 (unreleased) landed
Unify error messages
- 502e256f2262 19 (unreleased) cited
Optimize shared memory usage for WaitLSNProcInfo
- 75e82b2f5a6f 19 (unreleased) landed
Fix WaitLSNWakeup() fast-path check for InvalidXLogRecPtr
- ede6acef4967 19 (unreleased) landed
Fix incorrect function name in comments
- 23792d738158 19 (unreleased) landed
Add infrastructure for efficient LSN waiting
- 3b4e53a075ea 19 (unreleased) landed
Add pairingheap_initialize() for shared memory usage
- 8af3ae0d4b36 19 (unreleased) landed
Implement WAIT FOR command
- 447aae13b030 19 (unreleased) landed

Attachments

v1-0001-Use-WAIT-FOR-LSN-in-PostgreSQL-Test-Cluster-wait_.patch (application/octet-stream) patch v1-0001

Hi!

On Mon, Nov 3, 2025 at 5:13 PM Andres Freund <andres@anarazel.de> wrote:
> On 2025-11-03 16:06:58 +0100, Álvaro Herrera wrote:
> > On 2025-Nov-03, Alexander Korotkov wrote:
> >
> > > I'd like to give this subject another chance for pg19.  I'm going to
> > > push this if no objections.
> >
> > Sure.  I don't understand why patches 0002 and 0003 are separate though.
>
> FWIW, I appreciate such splits. Even if the functionality isn't usable
> independently, it's still different type of code that's affected. And the
> patches are each big enough to make that worthwhile for easier review.

Thank you for the feedback, pushed.

> One thing that'd be nice to do once we have WAIT FOR is to make the common
> case of wait_for_catchup() use this facility, instead of polling...

The draft patch for that is attached.  WAIT FOR doesn't handle all the
possible use cases of wait_for_catchup(), but I've added usage when
it's appropriate.

------
Regards,
Alexander Korotkov
Supabase