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https://issues.apache.org/jira/browse/DRILL-5304?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Abhishek Girish updated DRILL-5304:
-----------------------------------
    Attachment: query2_drillbit.log.txt
                query1_drillbit.log.txt

> Queries fail intermittently when there is skew in data distribution
> -------------------------------------------------------------------
>
>                 Key: DRILL-5304
>                 URL: https://issues.apache.org/jira/browse/DRILL-5304
>             Project: Apache Drill
>          Issue Type: Bug
>          Components: Query Planning & Optimization
>    Affects Versions: 1.10.0
>            Reporter: Abhishek Girish
>            Assignee: Padma Penumarthy
>         Attachments: query1_drillbit.log.txt, query2_drillbit.log.txt
>
>
> In a distributed environment, we've observed certain queries to fail 
> execution intermittently, with an assignment logic issue, when the underlying 
> data is skewed w.r.t distribution. 
> For example the TPC-H [query 
> 7|https://github.com/mapr/drill-test-framework/blob/master/framework/resources/Advanced/tpch/tpch_sf100/parquet/07.q]
>  failed with the below error:
> {code}
> java.sql.SQLException: SYSTEM ERROR: IllegalArgumentException: 
> MinorFragmentId 105 has no read entries assigned
> ...
>   (org.apache.drill.exec.work.foreman.ForemanException) Unexpected exception 
> during fragment initialization: MinorFragmentId 105 has no read entries 
> assigned
>     org.apache.drill.exec.work.foreman.Foreman.run():281
>     java.util.concurrent.ThreadPoolExecutor.runWorker():1145
>     java.util.concurrent.ThreadPoolExecutor$Worker.run():615
>     java.lang.Thread.run():744
>   Caused By (java.lang.IllegalArgumentException) MinorFragmentId 105 has no 
> read entries assigned
> {code}
> Log containing full stack trace is attached.
> And for this query, the underlying TPC-H SF100 Parquet dataset was observed 
> to be located mostly only on 2-3 nodes on an 8 node DFS environment. The data 
> distribution skew on this cluster is most likely the triggering factor for 
> this case, as the same query, on the same dataset does not show this failure 
> on a different test cluster (with possibly different data distribution). 
> Also, another 
> [query|https://github.com/mapr/drill-test-framework/blob/master/framework/resources/Functional/limit0/window_functions/bugs/data/drill-3700.sql]
>  failed with a similar error when slice target was set to 1. 
> {code}
> Failed with exception
> java.sql.SQLException: SYSTEM ERROR: IllegalArgumentException: 
> MinorFragmentId 66 has no read entries assigned
> ...
>   (org.apache.drill.exec.work.foreman.ForemanException) Unexpected exception 
> during fragment initialization: MinorFragmentId 66 has no read entries 
> assigned
> {code}



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