Hmm, maybe this is a bug in the HTTP/2 close code then, and somehow the
connection is not being closed if the client hangs up abruptly. I had a
quick look at the code though and I think it looks ok, but maybe some more
investigation is needed.
Stuart
On Tue, 3 Mar 2020 at 03:41, Nishant Kumar <nishantkumar35(a)gmail.com> wrote:
Yes, i have no control on client side. I am using HTTP2. I have
tried
increasing open file limit to 400k but that consumes all memory and system
hangs. I will probably try to put a nginx in front of Undertow and test.
setServerOption(UndertowOptions.ENABLE_HTTP2, true)
On Mon, Mar 2, 2020, 7:48 PM David Lloyd <david.lloyd(a)redhat.com> wrote:
> On Mon, Mar 2, 2020 at 7:56 AM Stan Rosenberg <stan.rosenberg(a)acm.org>
> wrote:
> >
> > Stuck in CLOSE_WAIT is a symptom of the client-side not properly
> shutting down [1].
>
> I would partially disagree. In the article you linked: "It all starts
> with a listening application that leaks sockets and forgets to call
> close(). This kind of bug does happen in complex applications." This
> seems to be essentially what's happening here: the server isn't
> completing the connection (for some reason), stranding the socket in
> `CLOSE_WAIT`.
>
> We can't assume that the client is abandoning the connection after
> `FIN_WAIT2` (the titular RFC violation); if the server stays in
> `CLOSE_WAIT`, then even if the client dutifully stays in `FIN_WAIT2`
> forever, the resolving condition still needs to be that the server
> shuts down its side of the connection.
>
> This diagram is a useful visual aid, mapping TCP states to the XNIO
> API:
>
https://www.lucidchart.com/publicSegments/view/524ec20a-5c40-4fd0-8bde-0a...
>
> --
> - DML
>
>