[jira] [Updated] (SPARK-23320) RANDOM pseudo environment variable has low resolution under Windows

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

     [ https://issues.apache.org/jira/browse/SPARK-23320?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Hyukjin Kwon updated SPARK-23320:
---------------------------------
    Labels: bulk-closed  (was: )

> RANDOM pseudo environment variable has low resolution under Windows
> -------------------------------------------------------------------
>
>                 Key: SPARK-23320
>                 URL: https://issues.apache.org/jira/browse/SPARK-23320
>             Project: Spark
>          Issue Type: Bug
>          Components: Spark Submit
>    Affects Versions: 2.1.1
>         Environment: Windows 7, Windows 10
> Spark 2.1.1
>            Reporter: Olivier Sannier
>            Priority: Minor
>              Labels: bulk-closed
>
> Under Windows, spark-submit.bat calls spark-class2.cmd which then runs org.apache.spark.launcher.Main to retrieve its output and place it into the SPARK_CMD variable.
> To do so, it uses a redirection to a temporary file whose name is created with this command:
> {{set LAUNCHER_OUTPUT=%temp%\spark-class-launcher-output-%RANDOM%.txt}}
> Note how it uses the %RANDOM% variable to get a hopefully unique name for the file that will get created.
> There are two issues with this however:
>  # if we have bad luck, we can get the same value RANDOM
>  # bad luck is quite easy to get if we submit numerous jobs at once, because the granularity of RANDOM is based on the current second, as indicated [here|https://blogs.msdn.microsoft.com/oldnewthing/20100617-00/?p=13673].
> When two concurrent spark-submit calls use the same generated file, one of them fails with a "file is in use" error message.
> I would thus suggest replacing the above line with these ones:
> {{rem Because random is based on the current time, second based, it may collide quite easily.}}
>  {{rem To avoid this, we retry until a non existent file name is found and we create that file as soon as possible}}
>  {{set laucher_try_count=5}}
>  {{:retry_launcher}}
>  {{set LAUNCHER_OUTPUT=%temp%\spark-class-launcher-output-%RANDOM%.txt}}
>  {{if not exist "%LAUNCHER_OUTPUT%" goto :launcher_success}}
>  {{set /A laucher_try_count -= 1}}
>  {{if %laucher_try_count% GTR 0 goto :retry_launcher}}
>  {{echo Could not generate a launcher output filename that does not already exists 1>&2}}
>  {{goto :eof}}
>  {{:launcher_success}}
>  {{echo rem > %LAUNCHER_OUTPUT%}}
> This code has been tried here and effectively solves the issue.
>  



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