The Integration Service creates each memory cache based on the configured cache size. When you create a session, you can configure the cache sizes for each transformation instance in the session properties.
The Integration Service might increase the configured cache size for one of the following reasons:
The configured cache size is less than the minimum cache size required to process the operation.
The Integration Service requires a minimum amount of memory to initialize each session. If the configured cache size is less than the minimum required cache size, then the Integration Service increases the configured cache size to meet the minimum requirement. If the Integration Service cannot allocate the minimum required memory, the session fails.
The configured cache size is not a multiple of the cache page size.
The Integration Service stores cached data in cache pages. The cached pages must fit evenly into the cache. Thus, if you configure 10 MB (1,048,576 bytes) for the cache size and the cache page size is 10,000 bytes, then the Integration Service increases the configured cache size to 1,050,000 bytes to make it a multiple of the 10,000-byte page size.
When the Integration Service increases the configured cache size, it continues to run the session and writes a message similar to the following message in the session log:
MAPPING> TE_7212 Increasing [Index Cache] size for transformation <transformation name> from <configured index cache size> to <new index cache size>.
Review the session log to verify that enough memory is allocated for the minimum requirements.
For optimal performance, set the cache size to the total memory required to process the transformation. If there is not enough cache memory to process the transformation, the Integration Service processes some of the transformation in memory and pages information to disk to process the rest.
Use the following information to understand how the Integration Service handles memory caches differently on 32-bit and 64-bit machines:
An Integration Service process running on a 32-bit machine cannot run a session if the total size of all the configured session caches is more than 2 GB. If you run the session on a grid, the total cache size of all session threads running on a single node must not exceed 2 GB.
If a grid has 32-bit and 64-bit Integration Service processes and a session exceeds 2 GB of memory, you must configure the session to run on an Integration Service on a 64-bit machine.