WSO2 DAS uses storm based distributed execution plan to store the processing logic to be used in a distributed mode deployment.
Writing an execution plan
The procedure for creating an execution plan is the same as that in Creating a Standalone Execution Plan. In addition, the following annotations are used in the Siddhi queries.
| Annotation | Description | Example |
|---|---|---|
@dist (parallel='<number of Storm tasks>) | The number of storm tasks in which the query should be run parallel. | @dist(parallel='4') |
@dist(execGroup='name of the group') | All the Siddhi queries in a particular execGroup will be executed in a single Siddhi bolt. | @dist(execGroup='Filtering') |
@Plan:dist(receiverParallelism='number of receiver spouts') | The number of event receiver spouts to be spawned for the Storm topology. | @Plan:dist(receiverParallelism='1') |
@Plan:dist(receiverParallelism='number of publisher spouts') | The number of event publisher spouts to be spawned for the Storm topology. | @Plan:dist(publisherParallelism='4') |
The following execution plan is populated with the above mentioned annotations.
| Note |
|---|
| Note: Every Siddhi query in a particular execGroup should have the same number of tasks as shown in the execution plan above ( e.g., parallel = '4' ). If the queries need to be distributed across different siddhi bolts, the execGroup names of the queries should differ from each other. |