[jira] [Commented] (FLINK-12126) Make relaxed rescaling behaviour accessible in REST interface

["Gary Yao (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-12126?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16824309#comment-16824309 ] 

Gary Yao commented on FLINK-12126:
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[~jshs] Are you using the rescaling feature in production?

> Make relaxed rescaling behaviour accessible in REST interface
> -------------------------------------------------------------
>
>                 Key: FLINK-12126
>                 URL: https://issues.apache.org/jira/browse/FLINK-12126
>             Project: Flink
>          Issue Type: Improvement
>          Components: Runtime / REST
>    Affects Versions: 1.7.2
>            Reporter: Joshua Schneider
>            Priority: Minor
>
> The REST handler for rescaling uses RescalingBehaviour.STRICT as a hard-coded parameter. This has the following consequences when a job is rescaled:
>  * All operators are set to the new parallelism. If at least one operator's max parallelism is less than the new parallelism, the rescale operation is aborted.
>  * Therefore, it is impossible to restrict the parallelism of a subset of operators (say, to one) in combination with rescaling.
> A different behaviour which fixes these issues, RescalingBehaviour.RELAXED, is already provided by the internal API. However, it appears to be unused.
> The REST interface should provide a parameter that selects the strategy. Alternatively, it could be a setting of the job.



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