When a Data Integration Service grid runs jobs in separate remote processes, how the Data Integration Service runs each job depends on the job type.
The Data Integration Service balances the workload across the nodes in the grid based on the following job types:
Workflows
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 LDTM component of the worker service process optimizes and compiles the mapping. The worker service process then communicates with the master compute node to dispatch the compiled mapping to a separate DTM process running on a worker compute node.
Deployed mappings
When you run a deployed mapping, the master service process uses round robin to dispatch each mapping to a worker service process. The LDTM component of the worker service process optimizes and compiles the mapping. The worker service process then communicates with the master compute node to dispatch the compiled mapping to a separate DTM process running on a worker compute node.
Profiles
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 distributes the mappings across the worker service processes. The LDTM component of the worker service process optimizes and compiles the mapping. The worker service process then communicates with the master compute node to dispatch the compiled mapping to a separate DTM process running on a worker compute node.
Ad hoc jobs, with the exception of profiles
When you run an ad hoc job, with the exception of profiles, the Data Integration Service uses round robin to dispatch the first request directly to a worker service process that runs on a node with both the service and compute roles. The worker service process runs the job in a separate DTM process on the local node. To ensure faster throughput, the Data Integration Service bypasses the master service process. When you run additional ad hoc jobs from the same login, the Data Integration Service dispatches the requests to the same worker service process.
You cannot run SQL queries or web service requests on a Data Integration Service grid that is configured to run jobs in separate remote processes.