Re: Extend documentation for pg_stat_replication.backend_xmin

Really nice,
Thanks a lot for the info and review.
Taken into the patch.

Regards,
Renzo Dani

On Thu, Oct 16, 2025 at 5:32 AM Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:

> On Thu, Oct 16, 2025 at 12:47 AM Renzo Dani <arons7(at)gmail(dot)com> wrote:
> >
> > Hi,
> > recently I had some issue understanding what was going on with a replica
> and the reported xmin.
> > I have than created a patch to better specify the value expected into
> the pg_stat_replication.backend_xmin field.
>
> +1
>
> + This field will be null if a replication slot is used; in that
> case, the xmin is available through <link
> linkend="view-pg-replication-slots">pg_replication_slots</link>.
>
> I think it would be better to also mention that this field is null
> when hot_standby_feedback is disabled.
>
> Also, <literal> tags should be used for "xmin", and a newline should
> be added to avoid an overly long line.
>
> Based on the above comments, how about revising it as follows?
>
> + This field will be null if a replication slot is used (in this
> case,
> + the standby's <literal>xmin</literal> is shown in
> + <link
> linkend="view-pg-replication-slots">pg_replication_slots</link>)
> + or if <varname>hot_standby_feedback</varname> is disabled.
>
> Regards,
>
> --
> Fujii Masao
>