On Thu, Oct 16, 2025 at 8:07 AM Renzo Dani <[email protected]> wrote:
> 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 <[email protected]> wrote: > >> On Thu, Oct 16, 2025 at 12:47 AM Renzo Dani <[email protected]> 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 >> > I think I did it the wrong way with the patches. So here again with all in one file. Sorry for that. Regards Renzo
From dfd9ba68bc52b8d0a78908227084520cad98cea3 Mon Sep 17 00:00:00 2001 From: Renzo Dani <[email protected]> Date: Thu, 16 Oct 2025 08:26:14 +0200 Subject: [PATCH v3] Extend documentation for pg_stat_replication.backend_xmin --- doc/src/sgml/monitoring.sgml | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index dc4fc29466d..d5f0fb7ba7c 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -1287,6 +1287,10 @@ description | Waiting for a newly initialized WAL file to reach durable storage <para> This standby's <literal>xmin</literal> horizon reported by <xref linkend="guc-hot-standby-feedback"/>. + 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. </para></entry> </row> -- 2.43.0
