Using a Local Cache for Queries
If you have a large dimension table you can load the dimension table's data into a cache, and use the cache to look up surrogate keys. Using a cache improves performance compared to performing lookups directly to the dimension table with Query DB.
A local cache is a temporary cache which is only used during the execution of the Query Cache stage. It looks up data in the cache based on key fields and lookup conditions and returns data from matching records in the cache, adding the cache record's data to the record in the dataflow. Use a local cache instead of global cache if it is only going to be used in one dataflow or if the lookup table changes frequently.
To use a local cache for queries: