Allocating Sufficient Space for the Temporary Files

You need different amounts of space for the temporary files during each cube build phase.
  • During the Data Read phase, the source data is read into a temporary work file based on the model structure. Insufficient disk space and database connectivity can cause problems at this stage.
  • During the Metadata Update phase, the contents of the temporary work file are compared to the categories in the model, to see which ones go into the cube, and a copy of the file is created. The original work file is only deleted after processing is complete and eligible categories are inserted into the cube. Insufficient disk space and lack of memory can cause problems at this stage.
  • During the Data Update phase, before the data points in the temporary work file can be inserted into the partitioned cube, the data must be sorted and consolidated. This requires several passes through the temporary file. The most common issue during this phase is low system memory.

There is a formula you can use to estimate the amount of space to allocate for the temporary files. If {([(A*4)+(B*4)+(C*16)+8]*D)/1024/1024}*2 is greater than 1431, the space calculation is that number plus E. If the calculated result is less than or equal to 1431, the required space is that number (do not add E).

Taking the test model as an example, the calculated space requirement is 7047 MB, given the following input values:

  • A = the total number of dimensions
  • B = the number of dimension views associated with the PowerCube
  • C = the number of regular measures (calculated measures are not counted)
  • D = the number of input records for all transactional data sources
  • E = 1431; the WorkFileMaxSize setting divided by 1024 * 1024 (MB)

To this number, you must add sufficient space for the PowerCube and the model checkpoint files: 7 GB + 20% for the former, and a number equal to the model working space for the latter.

We recommend that you point the Sort directory to the same location as the Data Temporary File, with all other Cognos® Transformer directory locations pointing to another drive. You should then use a system performance monitor, during the cube build, to check the amount of available disk space in the three cube build phases.