The master thread creates one or more transformation threads for each partition. Transformation threads process data according to the transformation logic in the mapping.
The master thread creates transformation threads to transform data received in buffers by the reader thread, move the data from transformation to transformation, and create memory caches when necessary. The number of transformation threads depends on the partitioning information for each pipeline.
Transformation threads store transformed data in a buffer drawn from the memory pool for subsequent access by the writer thread.
If the pipeline contains a Rank, Joiner, Aggregator, Sorter, or a cached Lookup transformation, the transformation thread uses cache memory until it reaches the configured cache size limits. If the transformation thread requires more space, it pages to local cache files to hold additional data.
When the PowerCenter Integration Service runs in ASCII mode, the transformation threads pass character data in single bytes. When the PowerCenter Integration Service runs in Unicode mode, the transformation threads use double bytes to move character data.