1. Database Administrator's Guide for Oracle Essbase
  2. Block Storage Calculation Optimization
  3. Essbase Caches and Calc Performance

Essbase Caches and Calc Performance

To optimize calculation performance, especially for large calculations, Essbase uses caches to coordinate memory usage. Ensure that the calculator cache, if used, is large enough to optimize calculations. Review how the index cache, data cache, dynamic calculator cache, and application cache may be relevant.

When calculating a cube, Essbase uses approximately 30 bytes of memory per member in the outline. So if the cube has 5,000 members, Essbase needs approximately 150 KB of memory to calculate it.

Note:

You can avoid excess memory use by combining calculation scripts. You can obtain good performance by using parallel calculation with a single calculation script. See Using Parallel Calculation.

Essbase uses memory to optimize calculation performance, especially for large calculations. The amount of memory used is not controllable, except by altering the size of the cube outline. However, you can ensure that the memory cache sizes enable Essbase to optimize the calculation.

Essbase uses the following caches to coordinate memory usage:

  • Calculator cache.

    When you first calculate a cube, the size of the calculator cache is significant for calculation performance. If possible, ensure that the calculator cache is large enough for Essbase to use the optimal calculator cache option.

    Refer to CALCCACHE configuration and SET CACHE command.

  • Dynamic calculator cache. Refer to DYNCALCCACHEMAXSIZE application configuration property.

  • Index cache. If the cube is large, the default index cache is not large enough to provide optimum calculation performance. Refer to INDEXCACHESIZE application configuration property, or MaxL alter database set index_cache_size.

  • Data cache. Refer to DATACACHESIZE application configuration property, or MaxL alter database set data_cache_size.

  • Data file cache.

  • Application cache. If hybrid mode is used in block storage cubes, the application cache can help you manage memory usage for retrievals. The application cache is similar to the aggregate storage cache; for more information, refer to Aggregate Storage Cache.