Informatica Common Components Lookup cache two use the persistent lookup cache

You can configure the Lookup transformation to use a non-persistent or permanent cache. After a successful session based on the Find cache persistent attribute, PowerCenter will save or delete the lookup cache file.

If the lookup table does not change between sessions, you can configure the Lookup transformation to use the persistent lookup cache. PowerCenter saves and re-uses the cache file during the session, eliminating the time it takes to read the lookup table.

Using non-persistent caches

By default, PowerCenter uses a non-persistent cache when caching is enabled in the Find transformation. At the end of the session, PowerCenter deletes the cache file. The next time you run the session, PowerCenter will build the memory cache from the database.

Use permanent cache

If you are saving and reusing cache files, you can configure the transformation to use a persistent cache. If you know that the lookup table does not change during the session, you can use the persistent cache.

PowerCenter the first time a session is run with a persistent lookup cache, it saves the cache file to disk without deleting it. PowerCenter the next time the session is run, the memory cache is built from the cache file. If the lookup table changes occasionally, you can override the session properties to re-cache lookups from the database.

When you use the persistent lookup cache, you can specify a name for the cache file. When you specify a named cache, you can find the cache through session sharing.

If the cache cannot be reused by PowerCenter, it will be re-cached from the database to find or terminate the session based on the mapping and session properties.

How a named or unnamed cache handles permanent caches:

Cache cache

mapping or session changes between sessions	named	not named
PowerCenter cannot locate the cache file.	Rebuild the cache.	Rebuild the cache.
Enable or disable the Enable High precision option in the session properties.	Causes the session to fail.	Rebuild the cache.
Edit the conversion in Mapping Designer, Mapplet Designer, or reusable transformation Developer. *	Causes the session to fail.	Rebuild the cache.
Edit mappings (except for lookup conversions).	Re-use the cache.	Rebuild the cache.
Change the database connection or the file location used to access the lookup table.	Causes the session to fail.	Rebuild the cache.
Change the PowerCenter Server data movement mode.	Causes the session to fail.	Rebuild the cache.
Change the order of arrangement in Unicode mode.	Causes the session to fail.	Rebuild the cache.
Change the PowerCenter Server code page to a compatible code page.	Re-use the cache.	Re-use the cache.
Change the PowerCenter Server code page to an incompatible code page.	Causes the session to fail.	Rebuild the cache.
* Edit attributes such as conversion instructions or port descriptions that do not affect permanent cache processing.

Informatica Common Components Lookup cache two use the persistent lookup cache