Re: pg_stat_replication.*_lag sometimes shows NULL during active replication

[Fujii Masao]

On Wed, Mar 25, 2026 at 4:03 PM Shinya Kato <shinya11.k...@gmail.com> wrote:
> Thanks for the updated patch. LGTM.
>
> Regarding the backpatch, I'd personally appreciate it if the walsender.c 
> changes were backpatched to stable branches. As you noted, it don't fully 
> solve the reported issue, but they do help reduce the cases where lag columns 
> in pg_stat_replication unexpectedly become NULL.
>
> Even a partial mitigation in the back branches would be valuable for users 
> running stable releases.

+1

I've split the changes into two patches.

Patch 0001 fixes premature NULL lag reporting in walsender. I will commit it
and backpatch it to all supported branches.

Patch 0002 avoids sending duplicate WAL locations in standby status replies.
I will commit this to master only.

Regards,

-- 
Fujii Masao

v7-0002-Avoid-sending-duplicate-WAL-locations-in-standby-.patch
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v7-0001-Fix-premature-NULL-lag-reporting-in-pg_stat_repli.patch
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