[jira] [Updated] (DRILL-855) Improve work assignment parallelization

["Aditya Kishore (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/DRILL-855?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Aditya Kishore updated DRILL-855:
---------------------------------

    Attachment: DRILL-855-Improve-work-assignment-parallelization.patch

> Improve work assignment parallelization
> ---------------------------------------
>
>                 Key: DRILL-855
>                 URL: https://issues.apache.org/jira/browse/DRILL-855
>             Project: Apache Drill
>          Issue Type: Improvement
>            Reporter: Aditya Kishore
>            Assignee: Aditya Kishore
>         Attachments: DRILL-855-Improve-work-assignment-parallelization.patch
>
>
> Currently if only a small number of endpoints have data affinity, all the work units get assigned to this small subset leaving other endpoints in the cluster underutilized.
> It will lead to poor query performance since the level of parallelization is reduced below what is otherwise possible.
> This JIRA intend to modify the assignment to do a slightly more equitable distribution of work fragments among all available nodes while slightly favoring the nodes with data affinity.
> This \*favor\* is controlled by the setting {{"drill.exec.work.affinity.factor"}} (defaults to 1.2f).
> As an example, let's say that there are 2 endpoints of which only one is with affinity and 10 work fragments. In the current scheme of things, all of these work fragments will get assigned to the single node with affinity. With the modified scheme and with default affinity factor of 1.2, it will get 20% more assignment that it would get under equal distribution (i.e. 6:4 instead of 5:5).



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