Database Reference
In-Depth Information
Persistent cache - the permanent one
You can configure caches to permanently save data. By default, caches are created as non-
persistent, that is, they will be deleted once the session run is complete. If the lookup table
or file does not change across the session runs, you can use the existing persistent cache.
Suppose that you have a process that is scheduled to run every day and you are using a
Lookup transformation to look up a reference table that is not supposed to change for 6
months. When you use a nonpersistent cache every day, the same data will be stored in
cache. This will waste time and space every day. If you choose to create a persistent cache,
Integration Service makes the cache permanent in the form of a file in the
$PMCacheDir
location, so you save the time required to create and delete the cache memory every day.
When the data in the lookup table changes, you need to rebuild the cache. You can define
the condition in the session task to rebuild the cache by overwriting the existing cache. To
rebuild the cache, you need to check the rebuild option in the session property, as discussed
