[jira] [Resolved] (SPARK-18690) Backward compatibility of unbounded frames

["Reynold Xin (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/SPARK-18690?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Reynold Xin resolved SPARK-18690.
---------------------------------
       Resolution: Fixed
         Assignee: Maciej Szymkiewicz
    Fix Version/s: 2.1.0

> Backward compatibility of unbounded frames
> ------------------------------------------
>
>                 Key: SPARK-18690
>                 URL: https://issues.apache.org/jira/browse/SPARK-18690
>             Project: Spark
>          Issue Type: Improvement
>          Components: PySpark, SQL
>    Affects Versions: 2.1.0
>            Reporter: Maciej Szymkiewicz
>            Assignee: Maciej Szymkiewicz
>            Priority: Minor
>             Fix For: 2.1.0
>
>
> SPARK-17845 introduced constant values to mark unbounded frame. This can break backward compatibility on some systems:
> In Spark <= 2.0:
> -  {{UNBOUNDED PRECEDING}} is {{-sys.maxisze}}
> -  {{UNBOUNDED FOLLOWING}} is {{sys.maxisze}}
> On 64 bit systems {{-sys.maxisze}} is typically equal to  (1 << 63) - 1, on 32 bit systems (1 << 31) - 1 (https://docs.python.org/3/library/sys.html#sys.maxsize).
> After SPARK-17845 this values are
> -  {{UNBOUNDED PRECEDING}} is -(1 << 63)
> -  {{UNBOUNDED FOLLOWING}} is (1 << 63) - 1
> As a result on many systems current code won't no longer use UNBOUNDED PRECEDING frame.
> We can use following values to ensure backward compatibility:
> - {{UNBOUNDED PRECEDING}} =  {{max(-sys.maxsize, _JAVA_MIN_LONG)}}
> - {{UNBOUNDED FOLLOWING}} =  {{min(sys.maxsize, _JAVA_MAX_LONG)}}
> Pros:
> - Prevents hard to spot errors in the user code.
> Cons:
> - Unnecessary complicated rules in the Spark code.



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