Table of Contents

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  1. Preface
  2. Analyst Service
  3. Content Management Service
  4. Data Integration Service
  5. Data Integration Service Architecture
  6. Data Integration Service Management
  7. Data Integration Service Grid
  8. Data Integration Service Applications
  9. Metadata Manager Service
  10. Model Repository Service
  11. PowerCenter Integration Service
  12. PowerCenter Integration Service Architecture
  13. High Availability for the PowerCenter Integration Service
  14. PowerCenter Repository Service
  15. PowerCenter Repository Management
  16. PowerExchange Listener Service
  17. PowerExchange Logger Service
  18. Reporting Service
  19. Reporting and Dashboards Service
  20. SAP BW Service
  21. Search Service
  22. System Services
  23. Test Data Manager Service
  24. Web Services Hub
  25. Application Service Upgrade
  26. Application Service Databases
  27. Connecting to Databases from Windows
  28. Connecting to Databases from UNIX
  29. Updating the DynamicSections Parameter of a DB2 Database

Cache Memory

Cache Memory

The DTM process creates in-memory index and data caches to temporarily store data used by the following transformations:
  • Aggregator transformation (without sorted input)
  • Rank transformation
  • Joiner transformation
  • Lookup transformation (with caching enabled)
You can configure memory size for the index and data cache in the transformation properties. By default, the PowerCenter Integration Service determines the amount of memory to allocate for caches. However, you can manually configure a cache size for the data and index caches.
By default, the DTM creates cache files in the directory configured for the $PMCacheDir service process variable. If the DTM requires more space than it allocates, it pages to local index and data files.
The DTM process also creates an in-memory cache to store data for the Sorter transformations and XML targets. You configure the memory size for the cache in the transformation properties. By default, the PowerCenter Integration Service determines the cache size for the Sorter transformation and XML target at run time. The PowerCenter Integration Service allocates a minimum value of 16,777,216 bytes for the Sorter transformation cache and 10,485,760 bytes for the XML target. The DTM creates cache files in the directory configured for the $PMTempDir service process variable. If the DTM requires more cache space than it allocates, it pages to local cache files.
When processing large amounts of data, the DTM may create multiple index and data files. The session does not fail if it runs out of cache memory and pages to the cache files. It does fail, however, if the local directory for cache files runs out of disk space.
After the session completes, the DTM releases memory used by the index and data caches and deletes any index and data files. However, if the session is configured to perform incremental aggregation or if a Lookup transformation is configured for a persistent lookup cache, the DTM saves all index and data cache information to disk for the next session run.