Re: Fix lag columns in pg_stat_replication not advancing when replay LSN stalls

On Sun, Oct 19, 2025 at 2:04 AM Shinya Kato <shinya11(dot)kato(at)gmail(dot)com> wrote:
> Thank you for the patch. I have one comment.
>
> + if (lag_tracker->overflowed[head].lsn > lsn)
> + return now - lag_tracker->overflowed[head].time;
>
> Could this return a negative value if the clock somehow went
> backwards? The original code returns -1 in this case, so I'm curious
> about this.

Thanks for the review!

Yes, you're right. So I've updated the patch so that -1 is returned
when the current time is earlier than the time in the overflow entry,
treating it as "no new sample found".

Regards,

--
Fujii Masao