Clusternig with JNDI problem

Question

I have a requierment to have a synchronous transaction where there is a
          daemon/process quering for new rows in a table (running constantly).
          When a new row shows up we need to remove it and do some business logic
          in an EJB. If the EJB fails, we dont want the rows removed (so we will
          rollback the changes).
          We are plannnig on registering this service as a thread (and probably
          binding indo the JNDI tree, so we can get to the service). The system
          will be clustered, and we want to make sure that only one of the
          clusters is running at a time, but if the server that is running goes
          down, we want another in the cluster to take over.
          Finally my question:
          I have looked at the ejb2.0 spec some but havent had the time to read it
          in much detail.
          Is there an easier solution to this problem than the one described?
          Is there something in weblogic that allows clusters to communicate with
          eachother so notification of a server going down can be handled and the
          responsibility of the service can be picked up by another server?
          thanks for any help you can offer
          -chris
          

Answer 1

The problem you describe is one of the weak points in the J2EE spec and in
          Weblogic clusters in particular. Usually the best solution is to use a
          timer on all server instances and let the database coordinate the
          concurrency of the "polling" logic such that only one server will "find" the
          data when it is available, although at different points, different servers
          will find the data. Then the only variable is the timer delay. This seems
          to be the most disaster-proof and scalable.
          Cameron Purdy
          Tangosol, Inc.
          http://www.tangosol.com
          +1.617.623.5782
          WebLogic Consulting Available
          "chris humphrey" <[email protected]> wrote in message
          news:[email protected]...
          > I have a requierment to have a synchronous transaction where there is a
          > daemon/process quering for new rows in a table (running constantly).
          > When a new row shows up we need to remove it and do some business logic
          > in an EJB. If the EJB fails, we dont want the rows removed (so we will
          > rollback the changes).
          >
          > We are plannnig on registering this service as a thread (and probably
          > binding indo the JNDI tree, so we can get to the service). The system
          > will be clustered, and we want to make sure that only one of the
          > clusters is running at a time, but if the server that is running goes
          > down, we want another in the cluster to take over.
          >
          > Finally my question:
          >
          > I have looked at the ejb2.0 spec some but havent had the time to read it
          > in much detail.
          >
          > Is there an easier solution to this problem than the one described?
          >
          > Is there something in weblogic that allows clusters to communicate with
          > eachother so notification of a server going down can be handled and the
          > responsibility of the service can be picked up by another server?
          >
          > thanks for any help you can offer
          > -chris
          >