5 Replies Latest reply: Feb 26, 2013 7:46 PM by name_and_address_withheld RSS

    Essbase Memory issue

      Hi All:
      I have an Essbase BSO cube with 35 G of page files and 6 G of index files. The version is The data cache setting is 8G. The index cache setting is 6G. Now the issue is the memory for the essvr.exe service is about 16G and the memory is not released when no activities at the cube. The server has about 24G memory. Now I need to add two duplicate cube with the same configure to the server which makes the server memory always as 98%.
      My questions are:
      1. Is memory required equal to data cache + index cache + data file cache? How about the calc cache? Currently Calc cache high is 2G.
      2. Why the memory did not get released if there is no activity?
      3. What is the optimal setting for the caches? Now the index cache hit ratio is 100% and data cache hit ratio is 50%.
      4. What else can I do except asking sys admins to add more memories?

      PS. The cube is reset every night and reload all 35G data. After that an Agg is run.


      Edited by: user8838483 on Feb 26, 2013 3:28 PM
        • 1. Re: Essbase Memory issue
          Does the cache have to be that big? I'll bet that it doesn't make that big of a difference in calc speed. Fast drives -- now those make a big difference in BSO calcs. Massive amounts of cache not so much.

          Should this even be a BSO database? That is getting pretty big for an agg it up database in BSO. You would be pleasantly shocked to see the size, memory requirements, and speed in ASO.

          You can always buy more memory but I'd think about the two above points before going down that path.

          Just some food for thought.


          Cameron Lackpour
          • 2. Re: Essbase Memory issue
            The DBAG says to make the index cache about the size of total index files. Is it correct?
            • 3. Re: Essbase Memory issue
              The problem when you follow those OLD settings is , When an application starts, the amount of memory set for the index cache is reserved and not lot go of until the application is stopped. So if you said give the index cache 2 gig, even if the actual index is 8 meg it will reserve the entire two gig. Especially on 64 it systems we find that many times smaller caches work better than large ones as it give the operating system more chance to manage memory better
              • 4. Re: Essbase Memory issue
                By setting cache sizes large you prevent the op system from keeping things in ram that are most frequent needed

                This is done using memory mapped io automatically.

                So set the caches low except during calculations then since you want to have the index files in ram
                Much more than the data files you would raise the index cache just b4 the calc and lower it afterwards. Do it for loads also (large ones not simple lock and sends)

                I agree with Cameron this might do better as ASO but I also note that the ratio of index file size to data file size is quite large consider increasing your block size.
                • 5. Re: Essbase Memory issue
                  The dbag is not the bible/gospel or silver bullet. It is what it says it is, a guide. There is nothing like some real world experience to highlight that. In other words, your cache settings are way to high. Although it may say you index needs to be this, and your data cache that, you have to take into account other factors. For example, how many apps you have running, what is your system specs, does increasing the cache actually make any difference in loads, calcs or retrieves. Especially with BSO there is such an art to how to develop and administer a cube.