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Memory allocation for lookup caches in partitioned session

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Lookup transformation is the most commonly used transformation in informatica . Earlier we discussed how we can increase the performance of lookup Transformation in informatica. We also discussed various Type of lookup Cache in informatica . In below article we will see how Memory allocation for lookup caches is done by informatica during partitioned session.

 

Memory allocation for lookup caches

Memory allocation for lookup caches

Check here for Types of lookup cache in Informatica

Memory allocation for lookup caches while running Partitioned Session

Static Lookup cache in informatica

When using Static Cache Partitioning

When using cache partitioning for  static cache lookup, PowerCenter creates separate cache for each partition. You can divide the total memory set for the lookup cache by number of partitions and set that value in the cache.

If Total cache requirement is 20 MB and number of partitions = 4, then set cache size = 5 MB.

When not using Static Cache Partitioning

When you are not using cache partitioning, PowerCenter Server requires as much memory for each partition as it does for a single partition pipeline. Hence, when you configure cache size, you enter the total memory requirements for the transformation.

If data cache memory is set to 2 MB and number of partitions = 4, then total cache memory required by PowerCenter is 8 MB.

Check here for Dynamic lookup vs Static lookup Cache

Dynamic Lookup cache in informatica

When using Dynamic Cache Partitioning

When using cache partitioning for lookup, PowerCenter creates separate cache for each partition. Hence, you can divide the total memory set for the lookup cache by number of partitions and set that value in the cache.

For Example : If the total cache requirement is 20 MB and number of partitions = 4, set cache size = 5 MB.
In this cache, PowerCenter will create 4 memory caches each of size 5 MB.

When not using Dynamic Cache Partitioning

When you are not using cache partitioning, PowerCenter Server creates one memory cache and one disk cache for each transformation. All partitions share the memory and disk cache. When you configure the cache size, enter the total memory requirements in the transformation or on the Mapping tab in the session properties.
For Example :  If data cache is set to 2 MB and number of partitions = 4, then a memory cache of size 2 MB will be created.

More Information Cache Partitioning in Lookup Transformation

The Integration Service uses cache partitioning when the following is true:

  • You create a hash auto-keys partition to point at the Lookup transformation.
  • The lookup condition contains only equality operators.
  • The database is configured for case-sensitive comparison.

So in this article we saw how Memory allocation for lookup caches in partitioned session is performed.

The Author

Alisha Lamba

Hello Friends , I am Alisha Lamba .I love to write article on latest technologies like Informatica , ETL , data warehouse , SQL-PL SQL
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