Re: Wake up backends immediately when sync standbys decrease

Chao Li <li.evan.chao@gmail.com>

From: Chao Li <li.evan.chao@gmail.com>
To: Shinya Kato <shinya11.kato@gmail.com>
Cc: Fujii Masao <masao.fujii@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2026-02-01T22:44:29Z
Lists: pgsql-hackers

> On Feb 1, 2026, at 14:24, Shinya Kato <shinya11.kato@gmail.com> wrote:
> 
> Thank you for the reviews!
> 
> On Sat, Jan 31, 2026 at 12:28 AM Fujii Masao <masao.fujii@gmail.com> wrote:
>> This issue can occur not only when the number of sync standbys is reduced,
>> but also when the configured standby names change. For example, if the config
>> changes from "FIRST 2 (sby1, sby2)" to "FIRST 2 (sby1, sby3)",
>> waiters on sby2 should be released immediately. But, currently, there can
>> a delay before that happens. Right?
> 
> Yes, you're right, so I revised the comments and commit message.
> 
>>> My main concern is code duplication. The same block is added in three places. While the existing reload handling is already duplicated there, adding more logic on top makes the situation a bit worse from a maintenance perspective.
>>> 
>>> Would it make sense to factor the reload handling into a small helper, for example:
>> 
>> +1
> 
> I've updated it in the v2 patch.
> 
> 
> -- 
> Best regards,
> Shinya Kato
> NTT OSS Center
> <v2-0001-Wake-up-backends-immediately-when-synchronous_sta.patch>

Thanks for updating the patch. V2 LGTM.

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/







Commits

  1. Release synchronous replication waiters immediately on configuration changes.