Re: pg_stat_replication.*_lag sometimes shows NULL during active replication - Mailing list pgsql-hackers

From Shinya Kato
Subject Re: pg_stat_replication.*_lag sometimes shows NULL during active replication
Date
Msg-id CAOzEurT7E4fX5jrHza4+BZt5krEc-0b0vXdHRNCjwNnrDy8g_Q@mail.gmail.com
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In response to Re: pg_stat_replication.*_lag sometimes shows NULL during active replication  (Fujii Masao <masao.fujii@gmail.com>)
Responses Re: pg_stat_replication.*_lag sometimes shows NULL during active replication
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On Thu, Mar 26, 2026, 00:30 Fujii Masao <masao.fujii@gmail.com> wrote:
On Wed, Mar 25, 2026 at 4:03 PM Shinya Kato <shinya11.kato@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.

Thanks, LGTM.

Best regards,
Shinya Kato

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