The Integration Service creates index and data caches for the Aggregator, Rank, Joiner, Sorter, and Lookup transformations. When the session contains more than one partition, the transformation threads may be distributed to more than one node in the grid. To create a single data and index cache for these transformation threads, verify that the root directory and cache directory point to the same location for all nodes in the grid.
When the Integration Service creates a cache for a Lookup transformation in a shared location, it builds a cache for the first partition group, and subsequent partition groups use this cache. When you do not configure a shared location for the Lookup transformation cache files, each service process on a separate node fetches data from the database or source files to create a cache. If the source data changes frequently, the caches created on separate nodes can be inconsistent.