Sorry about this last email. It was for Sebastiaan but in another thread.
Cheers, Martin On 5/2/07, Martin Perez <[EMAIL PROTECTED]> wrote:
Sebastiaan, Yes you're right. I forgot to add something like isClosed() to your SynchronizedOutputStream so I can check if it's closed before writing. Anyways, I found that after a certain limit (for ex. 6000 -> 8000 users) the system starts to behave incorrectly. Some clients never get an answer from the server, some clients only receive partial data, and some of them really end. I guess I found the limit in the box, but attached are the source code files if someone wants to see the sample or simply spot something in it. Cheers, Martin On 5/2/07, Sebastiaan van Erk <[EMAIL PROTECTED]> wrote: > > Praveen Balaji wrote: > > The > > last few days I have been evaluating using CometProcessor to work like > an > > Async Servlet for me. I pick up the CometEvent object on BEGIN event > and > > process the whole request asynchronously. When I am done, I close the > I/O stream. > > > > > > I > > would like to know what the Tomcat developers and the developers in > general > > think about this approach. Is it a misuse of the API to process > requests > > asynchronously, outside of the event method? Are there any issues that > I should be cautious about? Synchronization issues? > > > > > > > See the mailing list archive of the last month and filter on "comet". > There have been quite a few posts on exactly this subject. > > There are multiple issues: > > 1) Closing the I/O stream (on the response) does not end the > request/response. It takes another 30-60 seconds before the event method > gets called with an END event leaving a lot of request open > unnecessarily. > > 2) Nothing is synchronized in Comet, so you have to do all > synchronization yourself. You have to make sure that you do not write to > the output stream after the event is closed (even though you may still > have the reference in your asynchronous application code). I seem to > have eliminated most issues by synchronizing access to the response > output stream and using the same lock around the event.close() method in > the event() method of the CometProcessor. However I still very > sporadically get a ClientAbortException/ClosedChannelException which > suggests that I've missed a place where synchronization is necessary. It > might not be possible to synchronize this though, because it could > happen deep inside Tomcat. The API has no information about what to > synchronize for asynchronous use. > > 3) If you rely on the POST method to send parameters to your > CometProcessor, then you have to parse the parameters yourself; there is > an issue that doing getParameter() on the request in the BEGIN event may > > return null because the request body has not yet been received by the > server at the moment of the getParameter() call. > > One of the Comet developers (Remy) suggests that it might be better to > just use normal servlets and buy some extra memory for the extra > threads. > > As far as the current API goes, I would say it is probably a "misuse", > though I would very much like to see the API improved so that this is no > longer the case. > > Regards, > Sebastiaan > > > Thanks, > > Praveen Balaji. > > > > > > > > > > > > > > > > __________________________________________________ > > Do You Yahoo!? > > Tired of spam? Yahoo! Mail has the best spam protection around > > http://mail.yahoo.com > > > > --------------------------------------------------------------------- > To start a new topic, e-mail: users@tomcat.apache.org > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > >
