5 Replies Latest reply: Apr 10, 2013 7:22 AM by Mihael RSS

    Few Question on Rac

    947991
      Hi Experts ,

      I am new to the RAC , wanted to clear some doubt : Version 10.2.0.4 , dedicated process
      Their is concept of local listener and Remote Listener in Rac. I understand these are used internally for load balancing. Please correct me If I am wrong.
      If I provide the user tns details and having the enteries of one node (node 1) only and that node ( node 1) is heavily loaded. In that case load balancing takes place at listener level ? If yes How. Since Generally their is shadow process (server process) is created on server after the listener hand shake is done. And that process directly communicated with client process. So In rac if load balancing takes place then how the client will connect to node 2.
      Their is concept of VIP. Generally it is used to provide the High Availability. If the user query is runnning on node 1 and node 1 crashes, without knowing the user it will proccess the query from node 2.
      What kind of query can be executed ? Select , Insert , delete update . I heard that select will be executed but insert delete and update will be failed . Is that correct.

      REgards
      Sourabh Gupta
        • 1. Re: Few Question on Rac
          Mihael
          Their is concept of local listener and Remote Listener in Rac. I understand these are used internally for load balancing. Please correct me If I am wrong.
          If I provide the user tns details and having the enteries of one node (node 1) only and that node ( node 1) is heavily loaded. In that case load balancing takes place at listener level ? If yes How.
          You connect to service, not to sid. The service can run on multiple instances. Each instance every minute connects to local and remote listeners (if defined) and updates its services and load. So listener can balance connections among instances.

          >
          Their is concept of VIP. Generally it is used to provide the High Availability. If the user query is runnning on node 1 and node 1 crashes, without knowing the user it will proccess the query from node 2.
          What kind of query can be executed ? Select , Insert , delete update . I heard that select will be executed but insert delete and update will be failed . Is that correct.
          In 10g clients connect to VIP. If node fails, its VIP moves to another node. TAF does not require VIP, it was availiable before 10g.
          • 2. Re: Few Question on Rac
            947991
            Hi Mihael,

            Thanks a lot . Failover is applicabel for all the DML and DDL .

            Insert, Update , Delete , Select etc.

            Regards
            Sourabh Gupta
            • 3. Re: Few Question on Rac
              FreddieEssex
              select only will be failed over.

              Any update/insert/delete will be rolled back and your application should handle the error code to retry the operation.
              • 4. Re: Few Question on Rac
                947991
                Hi Freddie,

                Thanks a lot.

                Regards
                Sourabh Gupta
                • 5. Re: Few Question on Rac
                  Mihael
                  Even if session's query failed-over to another instance, session context is lost. So application should care of this.