The PowerCenter Integration Service creates caches in memory for SAP/ALE IDoc Prepare transformations and SAP DMI Prepare transformations. The transformations receive inbound data from upstream transformations and prepare the segment data. The PowerCenter Integration Service stores this data in the cache.

Configure the cache size in the session properties. Default cache size is 10 MB. You can set the cache size equal to 20 percent of the available memory for the system. For optimum session performance, calculate the cache size based on factors such as processing overhead and the size of the source data.

If you configure a large cache size, the PowerCenter Integration Service may run out of memory. If you configure a cache size that is more than the available memory for the system, the PowerCenter Integration Service fails the session.

If the PowerCenter Integration Service requires more memory than the configured cache size, it stores overflow values in cache files. Since paging to disk can slow session performance, configure the cache size to store data in memory. You configure the directory where cache files are stored in the session properties. When the session completes, the PowerCenter Integration Service releases cache memory and deletes the cache files. You may find cache files in the cache directory if the session does not complete successfully.