Creating a STORM Based Distributed Execution Plan

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:
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.