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Parallel annotation

Syntax@dist(parallel=’no of parallel instances<int>’)
Description

This annotation specifies the execution parallelism of an execution group (i.e., the number of instances in which the executional elements of the execution group must be executed in parallel). Parallelism is always defined against an execution group. If no parallelism is specified, 1 is considered default. If specified, the number of instances of the execution group is created, and all these instances work in parallel. When defining parallelism, the following scenarios result in validation exceptions and application deployment is halted as a result.

  • A defined window is referenced within an execution group of which the parallelism is greater than 1.

  • An in-memory table is referenced within an execution group of which the parallelism is greater than 1.

  • A window query is included within an execution group of which the parallelism is greater than 1.

  • A pattern query within an execution group of which the parallelism is greater than 1.

  • A sequence query within an execution group of which the parallelism is greater than 1.

  • A join query within an execution group of which the parallelism is greater than 1.

  • Window within a partition query where window is not defined against the partitioned stream or the inner stream that belongs to an execution group of which the parallelism is greater than 1.

  • If different parallelism numbers are specified within the same group, application deployment is aborted with a validation exception.

Applicable LevelQuery
Example
Code Block
@info(name = ‘query-3')
@dist(parallel='2')
from TempStream [(roomNo >= 100 and roomNo < 110) and temp > 40 ]
select roomNo, temp
insert into HighTempStream;

Transport channel creation annotation

Syntax@App:transportChannelCreationEnabled('true|false')
DescriptionThis annotation specifies whether Stream Processor managers are allowed to create Kafka topics that are required for application deployment. By default, this is set to true and the topics are created when the application is deployed. If the annotation is set to false, you need to create the required intermediate topics before deploying the application. If the required topics do not exist when you deploy the application, the application deployment fails, and the deployment process is aborted.
Applicable LevelApplication
Example
Code Block
languagesql
@App:name('wso2-app')  @App:transportChannelCreationEnabled('false')	


Creating a distributed Siddhi application

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