Developer Mapping Guide

10.2.2
- 10.5.7
- 10.5.6
- 10.5.4
- 10.5
- 10.4.1
- 10.4.0
- 10.2.1

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Override the Maximum Parallelism for a Mapping

By default, the

Maximum Parallelism

property for each mapping is set to Auto. Each mapping uses the maximum parallelism value defined for the Data Integration Service. You can override the maximum parallelism value to define a maximum value for a particular mapping.

When maximum parallelism is set to different integer values for the Data Integration Service and the mapping, the Data Integration Service uses the minimum value of the two.

You might want to override the

Maximum Parallelism

property for a mapping for the following reasons:

You run a complex mapping that results in more threads than the CPU can handle.: The total number of parallel threads that can run for the complete mapping pipeline is the parallelism value multiplied by the number of pipeline stages. Each partition point adds an additional pipeline stage. A complex mapping with multiple Aggregator or Joiner transformations might have many pipeline stages. A large number of pipeline stages can cause the Data Integration Service to use more threads than the CPU can handle.
Mapping performance is satisfactory with fewer parallel threads for each pipeline stage.: When a single mapping runs with fewer parallel threads, more threads are available for the Data Integration Service to run additional jobs.
You want to define a suggested parallelism value for a transformation.: If you override the maximum parallelism for a mapping, you can define a suggested parallelism value for a specific transformation in the mapping. You might want to define a suggested parallelism value to optimize performance for a transformation that contains many ports or performs complicated calculations.
You want to define an execution instances value for an Address Validator or Match transformation.: If you override the maximum parallelism for a mapping, the Data Integration Service considers the execution instances value for an Address Validator or Match transformation in the mapping. You might want to define an execution instances value to optimize performance for the transformation.