When you run a session that uses an Aggregator transformation, the Integration Service creates the index and the data caches in memory to process the transformation. If the Integration Service requires more space, it stores overflow values in cache files.
You can use a numeric value for the cache, you can use a cache value from a parameter file or you can configure the Integration Service to set the cache size by using the Auto setting.
The Integration Service uses memory to process an Aggregator transformation with sorted ports. The Integration Service does not use cache memory. You do not need to configure cache memory for Aggregator transformations that use sorted ports.