3 Replies Latest reply: Dec 7, 2012 5:24 AM by name_and_address_withheld RSS

    Essbase Data Cache Setting

    Chinmay Joshi
      Hi Gurus,

      Need some suggestions from your side.. I have a BSO database with below details:

      Total Data Size : Around 10-15 Gig
      Block Size : 98 Kb

      I am using Buffered I/O with Bitmap Encoding..

      What should be the size of Data Cache I should use ? Currently with 400000 KB of data cache I am getting around .42 Hit Ratio on Data Cache ...

      Is it fine to increase Data Cache to Higher Value ? ..

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        • 1. Re: Essbase Data Cache Setting
          PriyaPeravali
          Hello Chinmay,

          I do not have the version details. Assuming this to be version 11, providing the below.

          Hope this document helps:

               What are the Best Practices to Tune a Block Storage (BSO) Database? (Doc ID 1130813.1)

          1. ACR (Average clustering Rate) should be as close to 1 as possible. If it is higher you can launch a dense restructure to de-fragment the database.
          2. Block Size should be between 8 and 100KB (can be more on 64 bit systems).
          3. Data cache should be 12.5% of the pag files.
          4. Index cache should be the same size as the ind files.
          5. You should have 1 Database per Application.

          Regards,
          Priya

          Edited by: PriyaPeravali on Dec 6, 2012 5:38 AM
          • 2. Re: Essbase Data Cache Setting
            sunil k
            I do not think you can directly improve Hit Ratio by increasing the data cache. Hit ratio is an indicator of what % of time ESSBASE is able to find the right block within the cache itself without having to read from disk.

            Per ESSBASE admin guide - “Check memory allocation. Add smaller amounts of memory at a time , if needed, because a smaller increment may have the same benefit as a large one. Large, incremental allocations of memory usually result in very little gain in the hit ratio.”

            You should rather try to assess if you are having any issues with essbase operations (data loads, calculations, retrievals etc.) because of data cache – analysis of those would give you a definite indication if you would really gain something by increasing the data cache.

            Thansk,
            Sunil
            • 3. Re: Essbase Data Cache Setting
              name_and_address_withheld
              I would ask, why are you concerned about the ratio? You can spin many wheels in search of the perfect configuration, but unless you are severely short on server resources, or load/calc/retrieval performance is impacted, I would not worry about it.

              Perhaps if you let us know what the problem is, we can help suggest other paths?