When you run a workflow instance, the master service process runs the workflow instance and non-mapping tasks. The master service process uses round robin to dispatch each mapping within a Mapping task to a worker service process. The worker service process optimizes and compiles the mapping. The worker service process then creates a DTM instance within a separate DTM process to run the mapping.

When you run a deployed mapping, the master service process uses round robin to dispatch each mapping to a worker service process. The worker service process optimizes and compiles the mapping. The worker service process then creates a DTM instance within a separate DTM process to run the mapping.

When you run a profile, the master service process converts the profiling job into multiple mapping jobs based on the advanced profiling properties of the Data Integration Service. The master service process then uses round robin to dispatch the mappings across the worker service processes. The worker service process optimizes and compiles the mapping. The worker service process then creates a DTM instance within a separate DTM process to run the mapping.

When you run ad hoc jobs, with the exception of profiles, the Data Integration Service uses round robin to dispatch the first request directly to a worker service process.

Ad hoc jobs include mappings run from the Developer tool or previews, scorecards, or drill downs on profile results run from the Developer tool or Analyst tool.

To ensure faster throughput, the Data Integration Service bypasses the master service process. The worker service process creates a DTM instance within a separate DTM process to run the job. When you run additional ad hoc jobs from the same login, the Data Integration Service dispatches the requests to the same worker service process.