On 08/05/2012 07:41, Mladen Turk wrote: > On 05/08/2012 08:34 AM, Costin Manolache wrote: >> On Mon, May 7, 2012 at 11:05 PM, Mladen Turk<mt...@apache.org> wrote: >> >>> >>> For real pause (stop accepting connections and wait till all sessions >>> times out) this can be done safely by setting 10 second timeout >>> on listening socket. It means that in worse case we would have >>> session-timeout + 10s. >> >> >> I see, you want a graceful shutdown, with a loadbalancer that uses the >> fact >> that the server rejects connections to indicate 'unhealthy' ( instead of >> some error code ). What about the listen backlog, even if you don't call >> accept it'll still ACK few connections that will timeout. >> > > The current patch I've send doesn't use timeout. > If paused a single connection will get accepted but not > processed thus behaving exactly like backlog. > Later if continued (pause during deploy) it'll be processed or > closed (exactly like backlog behaves). > > >> Sorry, never used pause(), the lbs I know use status code from the health >> check, and the server is supposed to keep accepting connections until the >> LB figures things out ( and to be really 'graceful' the LB could keep >> sending requests for established sessions for a while, but not new >> sessions >> ). >> >> Well - +1, as long as you're sure the close() not unblocking accept() bug >> is no longer there ( may have been 10 years ago in 1.1, can't remember >> :-) >> > > Well, the javadocs for ServerSocket.close() says: > Closes this socket. > Any thread currently blocked in accept() will throw a SocketException.
I did some svn / BZ archaeology. The unlocking of the acceptor was introduced [1] in response to a bug report [2]. It appears that this was indeed working around a long since fixed JVM bug [3]. Given this, I have no objections to Mladen's propose changes. I would ask that a note is added to the docs and the Javadoc that explains that pausing a socket effectively adds one to the current value of the backlog. The only downside I can see is if someone wants zero backlog on pause. That is no longer going to be possible. Mark [1] http://svn.apache.org/viewvc?view=revision&revision=283457 [2] https://issues.apache.org/bugzilla/show_bug.cgi?id=1418 [3] http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4344135 --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@tomcat.apache.org For additional commands, e-mail: dev-h...@tomcat.apache.org
