What is lookup cache in Informatica?

Lookup is a passive transformation used to look up data in a relational table or a flat file. The transformation may be connected or unconnected. It may be cached or uncached. If it is cached, it is called as lookup cache.

Why lookup cache needed?

Lookup is very expensive in terms of time and resource. Because, Informatica hits the database and fetches the entire set of rows for each record. So, after the lookup in cached, it takes whole set of rows to the Informatica server and stores it in a cache file. When it is needed for the next time, Informatica uses this cache file. So, like this way Informatica lookup cache saves the time and the resource of hitting the database again.

Types of Informatica lookup cache

There are four types of Informatica lookup cache. These are:

Static cache, Dynamic cache, Shared cache, persistent cache.

Static Cache: In static lookup cache, once a Cache is created the Integration Service always requests the Cache instead of Lookup Table. In case of static cache, we cannot insert and update the cache.

Dynamic Cache: Here we can insert or update rows in the cache, when we want to pass the row.

Shared Cache: Informatica server builds the cache memory for multiple lookup transformations in the mapping. Once the lookup is done for the first lookup then memory is released. We can share the lookup cache between multiple transformations.

Persistent Cache: In this case, Informatica server processes a lookup transformation. It saves the lookup cache files and reuses them the next time.