Re: [PATCH] Include application_name in "connection authorized" log message

Greetings,

* Robert Haas (robertmhaas(at)gmail(dot)com) wrote:
> On Wed, Jun 20, 2018 at 3:45 PM, Stephen Frost <sfrost(at)snowman(dot)net> wrote:
> > * Don Seiler (don(at)seiler(dot)us) wrote:
> >> In trying to troubleshoot the source of a recent connection storm, I was
> >> frustrated to find that the app name was not included in the connection
> >> messages. It is there in the log_line_prefix on the disconnection messages
> >> but I would prefer it be directly visible with the connection itself. With
> >> some guidance from Stephen Frost I've put together this patch which does
> >> that.
> >
> > Yeah, I tend to agree that it'd be extremely useful to have this
> > included in the 'connection authorized' message.
>
> I don't get it. It seems like a bad idea to me to copy information
> that can already be logged using log_line_prefix into the message
> itself. If we start doing that, we'll end up with duplicated
> information all over the place, and even worse, it won't be
> consistent, because different people will want different things
> duplicated into different messages.
>
> Am I missing something?

The issue here is exactly that at the point where we emit the
'connection authorized' message, we haven't processed generic GUCs from
the startup packet yet and therefore application_name isn't set as a
GUC and, as a result, isn't included in the 'connection authorized'
message, even if it's specified in log_line_prefix.

There's no way, today, to get the application name included in the
'connection authorized' message, which certainly seems unfortunate and a
bit surprising, hence this patch to fix that.

Thanks!

Stephen