3 Replies Latest reply on Jan 14, 2022 1:46 PM by dan.smith@informatica.com

    Restarting Logger Using Sequence and Restart in PWXCCL.CFG

    Don Michie Active Member

      We are using CDC Express for Oracle with separate Database/PowerExchange/PowerCenter machines.

      We are trying to determine how to recover in the event of a PowerExchange Node failure.

       

      I understand if we can take copies of closed CND files during our CAPX processing that we can restore those to a standby PWX node, rebuild the CDCT, do the registrations, then start the Listener and Logger.

       

      However the Logger restart point I am confused about.

       

      I see that the tokens in PWXCCL.CFG can be used to do this, but I cannot find specific information, and I know they are different per source and application.

       

      We can start the logger and see the Sequence/Restart HEX values.   We can see these values again at FILESWITCH.

      I have read that we can take the 1st 12 'digits' of the HEX Sequence to determine the 'SCN'.

       

      So if we have something like this in our PWX message logs:

       

      220114 152811 LNX64 3 PWX-33282 File switch because of time. Records 24133. Elapsed seconds 601

      220114 152811 LNX64 3 PWX-36940 Closed file /opt/informatica/pwx/AV/GDSADPRF/condense/GDSADPRF.CND.CP220114.T1518001.

      220114 152811 LNX64 3 PWX-36941 Records 23852. Commits 281. End sequence

                            D400000D7F6CF5000100000000FFFFFFFFFFFFFFFFFFFF00002D430016657300ACFFFF0000.

      220114 152811 LNX64 3 PWX-33256 CCLWTR File switch complete. Current restart tokens: Sequence

                            D400000D7F6CF5000100000000FFFFFFFFFFFFFFFFFFFF00002D430016657300ACFFFF0000 Restart

                            00000D7F6CE72FB096503EE2F0D4.

       

      And that is the last good file we have before failure, and I can recover the CDCT up to that CND file, and I want to special start the logger with tokens, what values should I put in for SEQUENCE_TOKEN and RESTART_TOKEN?

       

      Thanks, I'm sure it is somewhere, I just can't find it.

        • 1. Re: Restarting Logger Using Sequence and Restart in PWXCCL.CFG
          dan.smith@informatica.com Guru

          If you have used PWXUCDCT to derive a backup CDCT, and then used PWXUCDCT to restore that backup to the actual CDCT, then you don't need SEQUENCE_TOKEN and RESTART_TOKEN overrides.

          All you need to do is warm start PWXCCL.

           

          If you do want to use those token values for a special start or cold start, just use the tokens from the PWX-33256 message.  "Sequence" is the SEQUENCE_TOKEN, and "Restart" is the RESTART_TOKEN

           

          220114 152811 LNX64 3 PWX-33256 CCLWTR File switch complete. Current restart tokens: Sequence

                                D400000D7F6CF5000100000000FFFFFFFFFFFFFFFFFFFF00002D430016657300ACFFFF0000 Restart

                                00000D7F6CE72FB096503EE2F0D4.

          • 2. Re: Restarting Logger Using Sequence and Restart in PWXCCL.CFG
            Don Michie Active Member

            Thanks for the quick reply,

             

            So even though there is a lapse between the time the logger went down, and the new logger is running, rebuilding the CDCT from CND will tell the logger to begin reading in Oracle REDO?   Much simpler than I was making this out to be.   And to special start from the messages in the PWX message log, I don't need to convert anything to decimal from HEX, just put the tokens in exactly as I see them in the messages?

             

            If that is the case, you have made my job so much easier,

            Thanks --

            • 3. Re: Restarting Logger Using Sequence and Restart in PWXCCL.CFG
              dan.smith@informatica.com Guru

              PWXCCL writes checkpoints to CDCT when each CND file is closed.

              On a warmstart, PWXCCL restarts as of the most recent checkpoint in the CDCT.

               

              When you rebuild the CDCT using PWXUCDCT, that includes the relevant checkpoints.

              So after that, a warm start of PWXCCL will restart as of the tokens/checkpoint corresponding to last closed CND file.

              Most likely, that will be somewhere in Archive Logs.