By default, the Integration Service shares the cache for Lookup transformations in a mapping that have compatible caching structures. For example, if you have two instances of the same reusable Lookup transformation in one mapping and you use the same output ports for both instances, the Lookup transformations share the lookup cache by default.
When two Lookup transformations share an unnamed cache, the Integration Service saves the cache for a Lookup transformation and uses it for subsequent Lookup transformations that have the same lookup cache structure.
If the transformation properties or the cache structure do not allow sharing, the Integration Service creates a new cache.