Re: Add client connection check during the execution of the query

Hi,

On 2021-03-24 16:08:13 +1300, Thomas Munro wrote:
> ... Andres just asked me the same question, when we were discussing
> the pq_peekmessage() patch (v7).  I had remembered that POLLHUP didn't
> work for this type of thing, from some earlier attempt at something
> similar, and indeed on my first attempt to do that here as an
> alternative design, it did not work... with TCP sockets (localhost)...
> though it did work with Unix sockets.  Gah!  Then he pointed me at
> POLLRDHUP (a Linux only extension) and that did seem to work in all
> cases I tried.  But without that, this v8 patch doesn't seem to work
> on FreeBSD (TCP), and for the rest of the menagerie, who knows?
> Here's a sketch patch like that for discussion.
> It's frustrating, because this patch is so simple, and doesn't have
> v7's problem with pipelined queries.  Hmm.

It is indeed frustrating. I searched a bit for other OSs and POLLRDHUP
and I'm annoyed by responses from various OS folks of "You don't need
that, just read the data upon POLLIN...".


I don't like the feature not handling pipelining etc, nor does working
undetectedly only on linux seem like a great answer. I guess we could
have the template files tell us wether it work, or configure test it,
but brrr.

I'm mostly joking, and I've not read the thread, but I assume just
sending an empty NoticeResponse or error message has been brought up and
laughed out of the room?


> (I tried to make it work on Windows too by reading the manual, no idea
> if that part compiles or works).

If the patch had tests, cfbot might tell you :)

Greetings,

Andres Freund