Re: log spam with postgres_fdw

On Sun, Sep 15, 2019 at 11:14 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Jeff Janes <jeff(dot)janes(at)gmail(dot)com> writes:
> > When closing the local session which had used postgres_fdw over an ssl
> > connection, I get log spam on the foreign server saying:
> > LOG: could not receive data from client: Connection reset by peer
> > It is easy to reproduce, but you must be using ssl to do so.
> > On searching, I see that a lot of people have run into this issue, with
> > considerable confusion, but as far as I can see it has never been
> diagnosed.
>
> In
>
> https://www.postgresql.org/message-id/flat/3DPLMQIC.YU6IFMLY.3PLOWL6W%40FQT5M7HS.IFBAANAE.A7GUPCPM
>
>
Thanks, I had not spotted that one, I guess because the log message itself
was not in the subject so it ranked lower.

> we'd concluded that the issue is probably that postgres_fdw has no
> logic to shut down its external connections when the session closes.
> It's not very clear why the SSL dependency, but we speculated that
> adding an on_proc_exit callback to close the connection(s) would help.
>
>
It is easy to reproduce the ssl dependency without any FDW, just by doing a
kill -9 on psql. Apparently the backend process for unencrypted connections
are happy to be ghosted, while ssl ones are not; which seems like an odd
distinction to make. So should this be addressed on both sides (the server
not whining, and the client doing the on_proc_exit anyway?). I can take a
stab at the client side one, but I'm over my head on the ssl connection
handling logic on the server side.

Cheers,

Jeff