Re: Newly created replication slot may be invalidated by checkpoint

Amit Kapila <amit.kapila16@gmail.com>

From: Amit Kapila <amit.kapila16@gmail.com>

To: Masahiko Sawada <sawada.mshk@gmail.com>

Cc: "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>, Vitaly Davydov <v.davydov@postgrespro.ru>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>, "suyu.cmj" <mengjuan.cmj@alibaba-inc.com>, tomas <tomas@vondra.me>, michael <michael@paquier.xyz>, "bharath.rupireddyforpostgres" <bharath.rupireddyforpostgres@gmail.com>, Alexander Korotkov <aekorotkov@gmail.com>

Date: 2025-12-08T09:46:54Z

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 →

Prevent invalidation of newly synced replication slots.
- 3243c0177efb 17.8 landed
- 919c9fa13cd0 18.2 landed
- 851f6649cc18 19 (unreleased) landed
Prevent invalidation of newly created replication slots.
- 3510ebeb0dfa 17.8 landed
- 24cce33c332a 16.12 landed
- aae05622a7cb 15.16 landed
- 7406df60569f 14.21 landed
- d3ceb20846e4 18.2 landed
- 006dd4b2e5b3 19 (unreleased) landed
Fix re-distributing previously distributed invalidation messages during logical decoding.
- 45c357e0e85d 17.6 cited
Keep WAL segments by the flushed value of the slot's restart LSN
- 2090edc6f32f 17.6 cited
Keep WAL segments by slot's last saved restart LSN
- ca307d5cec90 18.0 cited

On Mon, Dec 8, 2025 at 12:53 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>
> On Fri, Dec 5, 2025 at 4:10 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > On Thu, Dec 4, 2025 at 12:12 PM Zhijie Hou (Fujitsu)
> > <houzj.fnst@fujitsu.com> wrote:
> > >
> > > Here are the updated patches for HEAD and 18. I did not add tests since, after
> > > applying the patch and resolving the issue, the only observable behavior is that
> > > the checkpoint will wait for another backend to create a slot due to the lwlock
> > > lock, so it seems not worth to test solely lwlock wait event (I could not find similar
> > > tests).
> > >
> >
> > Fair enough. The patch looks mostly good to me, attached are minor
> > comment improvements atop the HEAD patch. I'll do some more testing
> > before push.
> >
> > Sawada-san/Vitaly, do you have any opinion on patch or the direction
> > to fix? The idea is to get this fixed for HEAD and 18, then continue
> > discussion for other bank-branches and the remaining patches.
>
> +1
>

Thanks, Pushed. I'll continue thinking on how to fix it in branches
prior to 18 and other problems reported in this thread.

-- 
With Regards,
Amit Kapila.