What messages are exchanged in InMem Rep ?

Question

Hello..
          I'm measuring the performance of session state replication..
          I'd like to understand internal process for session replicaton..
          Please let me know
          how many message is exchanged for one replication.
          and if possible how long the message is and what's the content of the
          message in details..
          Thanks in advance..
          

Answer 1

Cameron Purdy <[email protected]> wrote:
          >> I'm measuring the performance of session state replication..
          >> I'd like to understand internal process for session replicaton..
          >> Please let me know
          >> how many message is exchanged for one replication.
          >> and if possible how long the message is and what's the content of the
          >> message in details..
          > Those details are not provided by BEA. It does not appear that "messages"
          > (as in JMS) are used. Most probably, the protocol is TCP or UDP based, so
          > you can measure packets with a network sniffer. It is widely assumed that
          > only inserted/modified/removed session entries are replicated, and those
          > only at the end of the HTTP request processing.
          I think WLS documenation mentions somewhere that point-to-point (TCP) is
          used for state replication and also it says:
          Use setAttribute to Change Session State
          In an HTTP servlet that implements javax.servlet.http.HttpSession, use HttpSession.setAttribute
          (which replaces the deprecated putValue) to change attributes in a session object. If you set
          attributes in a session object with setAttribute, the object and its attributes are replicated
          in a cluster using in-memory replication. If you use other set methods to change objects within
          a session, WebLogic Server does not replicate those changes. Every time a change is made to an
          object that is in the session, setAttribute() should be called to update that object across the
          cluster.
          Likewise, use removeAttribute (which, in turn, replaces the deprecated removeValue) to remove an
          attribute from a session object.
          > Peace,
          > Cameron Purdy
          > Tangosol, Inc.
          > http://www.tangosol.com/coherence.jsp
          > Tangosol Coherence: Clustered Replicated Cache for Weblogic
          > "dhlee" <[email protected]> wrote in message
          > news:[email protected]...
          >>
          Dimitri