Case study 33: Update statistics in replicated environment
  • Platforms: All
  • SAP RS version: 15.x
  • Background story: In replicated, Warm standby, environment, update statistics is done on both machines - primary and standby. I've been asking myself - would update statistics on primary be replicated on standby? By trying to find solution for that, I've stumble on also one interesting question regarding update statistics for Replication Server system database, RSSD, with different, oposite answers.
  • Solution: Update statistics is not replicated in warm standby environment. So, when You update statistics primary database, this new statistics will not go to the standby database server
    One interesting finding regarding update statistics of Replication Server system database, RSSD. Here are extracts from Sybase documentation:
    1. "You do not need to run update statistics on Replication Server RSSD tables. Running updates statistics on these tables can result in Replication Server errors if you run it while Replication Server attempts to access the RSSD tables. RSSD tables and their format are specific to Replication Server processing."
    2. "Execute the Adaptive Server update statistics command on the RSSD tables periodically if there are many RSSD changes."

    So, which statement would You consider as true? :-)
  • Conclusion: You can (or should) update primary and standby databases independently, or by using optdiag to transfer statistics from primary to secondary database.

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