[jira] [Resolved] (SPARK-20227) Job hangs when joining a lot of aggregated columns

["Hyukjin Kwon (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/SPARK-20227?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Hyukjin Kwon resolved SPARK-20227.
----------------------------------
    Resolution: Incomplete

> Job hangs when joining a lot of aggregated columns
> --------------------------------------------------
>
>                 Key: SPARK-20227
>                 URL: https://issues.apache.org/jira/browse/SPARK-20227
>             Project: Spark
>          Issue Type: Bug
>          Components: SQL
>    Affects Versions: 2.1.0
>         Environment: AWS emr-5.4.0, master: m4.xlarge, core: 4 m4.xlarge
>            Reporter: Quentin Auge
>            Priority: Major
>              Labels: bulk-closed
>
> I'm trying to replace a lot of different columns in a dataframe with aggregates of themselves, and then join the resulting dataframe.
> {code}
> # Create a dataframe with 1 row and 50 columns
> n = 50
> df = sc.parallelize([Row(*range(n))]).toDF()
> cols = df.columns
> # Replace each column values with aggregated values
> window = Window.partitionBy(cols[0])
> for col in cols[1:]:
>     df = df.withColumn(col, sum(col).over(window))
> # Join
> other_df = sc.parallelize([Row(0)]).toDF()
> result = other_df.join(df, on = cols[0])
> result.show()
> {code}
> Spark hangs forever when executing the last line. The strange thing is, it depends on the number of columns. Spark does not hang for n = 5, 10, or 20 columns. For n = 50 and beyond, it does.
> {code}
> 17/04/05 14:39:28 INFO ExecutorAllocationManager: Removing executor 1 because it has been idle for 60 seconds (new desired total will be 0)
> 17/04/05 14:39:29 INFO YarnSchedulerBackend$YarnDriverEndpoint: Disabling executor 1.
> 17/04/05 14:39:29 INFO DAGScheduler: Executor lost: 1 (epoch 0)
> 17/04/05 14:39:29 INFO BlockManagerMasterEndpoint: Trying to remove executor 1 from BlockManagerMaster.
> 17/04/05 14:39:29 INFO BlockManagerMasterEndpoint: Removing block manager BlockManagerId(1, ip-172-30-0-149.ec2.internal, 35666, None)
> 17/04/05 14:39:29 INFO BlockManagerMaster: Removed 1 successfully in removeExecutor
> 17/04/05 14:39:29 INFO YarnScheduler: Executor 1 on ip-172-30-0-149.ec2.internal killed by driver.
> 17/04/05 14:39:29 INFO ExecutorAllocationManager: Existing executor 1 has been removed (new total is 0)
> {code}
> All executors are inactive and thus killed after 60 seconds, the master spends some CPU on a process that hangs indefinitely, and the workers are idle.



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