Configure the amount of memory for a cache in the session properties. The cache size specified in the session properties overrides the value set in the transformation properties.
The amount of memory you configure depends on how much memory cache and disk cache you want to use. If you configure the cache size and it is not enough to process the transformation in memory, the Integration Service processes some of the transformation in memory and pages information to cache files to process the rest of the transformation. For optimal session performance, configure the cache size so that the Integration Service can process all data in memory.
If the session is reusable, all instances of the session use the cache size configured in the reusable session properties. You cannot override the cache size in the session instance.
Use one of the following methods to configure a cache size:
Use the calculator to estimate the total amount of memory required to process the transformation.
Auto cache memory.
Use auto memory to specify a maximum limit on the cache size that is allocated for processing the transformation. Use this method if the machine on which the Integration Service process runs has limited cache memory.
Configure a specific value for the cache size. Configure a specific value when you want to tune the cache size.
You configure the memory requirements differently when the Integration Service uses cache partitioning. If the Integration Service uses cache partitioning, it allocates the configured cache size for each partition. To configure the memory requirements for a transformation with cache partitioning, calculate the total requirements for the transformation and divide by the number of partitions.
The cache size requirements for a transformation may change when the inputs to the transformation change. Monitor the cache sizes in the session logs on a regular basis to help you tune the cache size.