At Mon, 22 Jun 2026 06:56:45 +0000, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com> wrote in
> Dear Peter,
>
> > Note that the latter includes pg_basebackup, pg_receivewal, and
> > pg_recvlogical, which feel generally similar to pg_createsubscriber.
>
> Hmm, but similar command pg_upgrade was included in the server app page.
>
> The page [1] defined that server commands are the command can be run on the same
> server with the postgres server process. IIRC, the command was categorized as
> "Server Application" because it assumed standby is running on the same machine.
>
> But... I think the command is located on the border between the server and the client.
> We should hear other opinions too.
>
> [1]: https://www.postgresql.org/docs/devel/reference-server.html
I also agree that pg_createsubscriber sits somewhere on the boundary
between server and client applications. If we were to draw a
distinction, one possible interpretation would be that server
applications are tools that access server resources beyond what a
regular client connection normally does. That seems broadly consistent
with the current classification, although pg_basebackup still feels
somewhat borderline under that interpretation.
I also wonder whether the server/client distinction is particularly
important here. A number of utilities seem to fall somewhere between
the two categories, and I'm not sure users pay much attention to that
classification when looking up commands.
Regards,
--
Kyotaro Horiguchi
NTT Open Source Software Center
