2 Replies Latest reply on Oct 17, 2010 12:17 PM by 751640

    TAF and FCF 11gr2 RAC


      I'm kind of confused with TAF and FCF concept please help me better understand this.Lets say i have a two node cluster in 11gr2 and i configured an (TAF) application service at server side using srvctl add service for a java application,now all client application connections will be through this service and will run on the prefered nodes providing the service and if the node/instance failed will run on the available nodes. Now my confusion is, RAC is handling the failover then why is that at application tier we need to enable FCF?as TAF is already configured by creating server side service?
        • 1. Re: TAF and FCF 11gr2 RAC

          TAF and FCF in Oracle 11gr2 RAC and Oracle 10g are the same high-availability features

          The Fast Connection Failover mechanism depends on the implicit connection cache feature. As a result, for Fast Connection Failover to be available, implicit connection caching must be enabled.

          When enabled, Fast Connection Failover provides:

          -Rapid detection and cleanup of invalid cached connections, that is, DOWN event processing
          -Load balancing of available connections, that is, UP event processing
          -Run-time work request distribution to all active Oracle RAC instances
          For FCF see this link

          Transparent Application Failover (TAF) is a feature of the Java Database Connectivity (JDBC) Oracle Call Interface (OCI) driver. It enables the application to automatically reconnect to a database, if the database instance to which the connection is made fails. In this case, the active transactions roll back.

          When an instance to which a connection is established fails or is shutdown, the connection on the client side becomes stale and would throw exceptions to the caller trying to use it. TAF enables the application to transparently reconnect to a preconfigured secondary instance creating a fresh connection, but identical to the connection that was established on the first original instance. That is, the connection properties are the same as that of the earlier connection. This is true regardless of how the connection was lost.

          For TAF see this link
          http://download.oracle.com/docs/cd/B19306_01/java.102/b14355/ocitaf.htm#BABGIDEE :)
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          • 2. Re: TAF and FCF 11gr2 RAC
            Thanks.As i already have a TAF configured at oracle server side what do i need to do from RAC perspective to make it FCF enabled irrespective of what connection pool we use?Do i have to reconfigure the services with no TAF parameters or attributes?You mean to say even though i have TAF enabled as i'm using JDBC thin client i won't be able to use this feature ,correct?Its all confusing ....