On Thu, Jul 4, 2013 at 5:52 PM, André Warnier <a...@ice-sa.com> wrote:
> Mark Thomas wrote: > >> On 04/07/2013 10:17, André Warnier wrote: >> >>> To me that means that at some point, there must be on the server side a >>> process or thread which is dedicated to this websocket client for as >>> long as it takes, and this process/thread in the meantime is no longer >>> available to process other HTTP requests. >>> (That's because the basic idea is that the "websocket application" on >>> the server side can keep sending messages asynchronously to the client - >>> and vice-versa - so I don't see how this can work with different >>> threads/processes on the server; but I'm not that smart, so it may be >>> that the implementation is smarter). >>> For that same reason, it would seem that the very concept of >>> "load-balancing" must be suspended once the websocket connection is >>> established. >>> >> >> The connection has to be kept open but you can use non-blocking IO to >> only allocate a thread to process data when there is data to process. >> >> The exact behaviour varies between Tomcat 7 and Tomcat 8. >> >> BIO 7 & 8 - 1 thread per connections, blocking IO, doesn't scale >> >> NIO / APR 7 - 1 thread per currently processed frame, non-blocking >> between frames, scales better >> >> NIO / APR 8 - threads only allocated where there is data to process, >> scales best >> > > "data to process" meaning an entire websocket "message" I suppose ? > > >> Note that JSR356 allows blocking writes. If the client or the server opt >> to send data using a blocking write then that will use a thread until >> the write completes. >> >> Load-balancers should cope perfectly happily with this. >> >> There is no upgrade or WebSocket support in AJP yet. >> >> > Thanks for these precisions. > > Another question while we're at it : > As I understand from the specs/docs, there are 2 kinds of messages : text > or "blob". > And I found that there are 2 ways of reading that data, corresponding to > these 2 types of messages. > However, I do not find anywhere a function or method or call which would > allow for example the server-side application to find out in advance if the > data currently available for reading is one or the other type. Did I miss > that somewhere, or do I misunderstand the specs/docs ? > The application is being notified. The container calls either onMessage(String/CharBuffer) or onMessage(byte[]/ByteBuffer) on the endpoint (or whatever is the exact API) > > > ------------------------------**------------------------------**--------- > To unsubscribe, e-mail: > users-unsubscribe@tomcat.**apache.org<users-unsubscr...@tomcat.apache.org> > For additional commands, e-mail: users-h...@tomcat.apache.org > >
