If the DTM cannot process a transformation in memory, it writes the overflow values to cache files. When the job completes, the DTM releases cache memory and usually deletes the cache files.

By default, the DTM stores cache files for Aggregator, Joiner, Lookup, and Rank transformations in the list of directories defined by the Cache Directory property for the Data Integration Service. The DTM creates index and data cache files. It names the index file

PM*.idx

, and the data file

PM*.dat

.

The DTM stores the cache files for Sorter transformations in the list of directories defined by the Temporary Directories property for the Data Integration Service. The DTM creates one sorter cache file.