Thursday, 4 October 2012

Types of Lookup Caches in Informatica


Lookup Caches in Informatica
Static cache
Dynamic cache
Shared cache
Persistent cache


Static cache
Static Cache is same as a Cached Lookup in which once a Cache is created the Integration Service always queries the Cache instead of the Lookup Table.
In Static Cache when the Lookup condition is true it return value from lookup table else returns Null or Default value. In Static Cache the important thing is that you cannot insert or update the cache.

Dynamic cache
In Dynamic Cache we can insert or update rows in the cache when we pass the rows. The Integration Service dynamically inserts or updates data in the lookup cache and passes the data to the target. The dynamic cache is synchronized with the target

Shared cache
When we use shared Cache Informatica server creates the cache memory for multiple lookup transformations in the mapping and once the lookup is done for the first lookup then memory is released and use that memory used by the other look up transformation.
We can share the lookup cache between multiple transformations. Unnamed cache is shared between transformations in the same mapping and named cache between transformations in the same or different mappings.

Persistent cache
If we use Persistent cache Informatica server processes a lookup transformation and saves the lookup cache files and reuses them the next time. The Integration Service saves or deletes lookup cache files after a successful session run based on whether the Lookup cache is checked as persistent or not
In order to make a Lookup Cache as Persistent cache you need to make the following changes
  • Lookup cache persistent: Needs to be checked
  • Cache File Name Prefix: Enter the Named Persistent cache file name
  • Re-cache from lookup source: Needs to be checked

Recache from database
If the persistent cache is not synchronized with the lookup table you can configure the lookup transformation to rebuild the lookup cache.

6 comments:

  1. very useful and nice

    ReplyDelete
  2. Very good information however screen shot of change mode of look up cache might me more useful.

    ReplyDelete

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