Adjust the Auto-Partitioning Parameters

You can use the Auto-Partition tab on the PowerCube property sheet for each cube in your model to test different settings and see which ones yield the best results for your situation.

Before you begin

Before you begin, ensure that any previously defined manual partitions are cleared, and that the optimization setting on the Processing tab of the PowerCube property sheet is set to Auto-partition.

Procedure

  1. Click the Auto-Partition tab and experiment with various test settings, as follows:
    • Specify an Estimated number of consolidated records. Consolidation combines records that contain identical non-measure values, reducing cube size and improving run-time performance. Start with the default. Later, you can check the log file to see the actual number.
    • Adjust the slider in the direction of Faster cube creation or Faster cube access, as appropriate for your current requirements. By default, the slider is centered.
    • Specify a Desired partition size, which is based on the consolidated record count. The default number of categories is 500,000 but you can reduce this number in incremental steps, testing various settings until you achieve acceptable run-time performance. When you build your cube, Cognos® Transformer automatically groups all categories into partitions of this size, in a way that is optimal for your model. Partitioning stops when the number of records in the summary partition drops below this specified partition size.
    • Specify the Maximum number of passes, beginning with either five (5), or one (1) pass for every manually defined partition level. The partitioning process continues, one pass per level, until this number is reached, or until subsequent consolidation passes fail to yield a further reduction in the summary partition size.
      Tip: Set this value to the minimum number of passes needed. If tests show that the last few passes did not significantly improve performance, decrease the number to achieve an appropriate balance between data access and cube build times.
  2. Click the Dimensions tab, select the dimensions that you want to include in your cube, and click OK.
  3. Click PowerCube Partition Status on the Tools menu, learn how the automatic partitioning algorithm has distributed your records during your partitioning tests, and act on the results. For example, if both your summary partition and your level-one partition have the same number of records, then the summary partition has not been consolidated. You need to increase the number of passes.
    Tip: You may want to perform some manual partitioning tests, comparing those results with the performance gained by auto-partitioning and choosing the best solution for your particular OLAP reporting situation.