Using the Log File to Analyze Processing Bottlenecks

The Cognos® Transformer log file provides useful information to help you diagnose the cause of processing bottlenecks during cube builds.

Complete the following procedure:

  1. Import these delimited-field data log files into a spreadsheet, such as Microsoft Excel:

    LogFileDirectory=f: \logfiles\

  2. In the resulting log file import, select the header of the E column and, if you are using Microsoft Excel, from the Data menu, click Filter and select the AutoFilter option.
  3. In the list, select either (NonBlanks) or one of the three phases in the process. The spreadsheet now shows only the timing information for your selection.
  4. Select several cells in the F column and select the Sum command, to add the timing values for your selected cells, as displayed in the lower toolbar.
  5. Repeat the above steps to examine each subphase. These appear in distinct blocks as follows, with each completing before the next subphase begins:
    • Data Read

      INITIALIZING CATEGORIES

      OPEN DATA SOURCE

      READ DATA SOURCE

      MARKING CATEGORIES USED

    • Metadata Update

      SORTING

      UPDATE CATEGORY AND PROCESS WORK FILE

      METADATA

    • Data Update

      CUBE UPDATE

      CUBE COMMIT

    Note: If the timing shown for TOTAL TIME (CREATE CUBE) is different from the timing for the separate phases, you can adjust for the time difference in the Cube Update phase.
  6. Assess how much time is spent on each phase. If you notice that, over time, cube builds are taking longer to complete even though the data set is relatively constant, compare each phase in the log files, to see where increases in build times are occurring.