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From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (FLINK-5520) Disable outer joins with non-equality predicates
Date Wed, 18 Jan 2017 10:10:26 GMT

    [ https://issues.apache.org/jira/browse/FLINK-5520?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15827772#comment-15827772
] 

ASF GitHub Bot commented on FLINK-5520:
---------------------------------------

Github user fhueske commented on the issue:

    https://github.com/apache/flink/pull/3141
  
    The difference between failing during validation and translation is the code line that
throws the exception. A check during validation causes an exception on the line that is responsible
for the error. A check during translation throws an exception much later in the user program.
    
    Regarding the check in the rule: IMO, each rule must ensure that is does not translate
the query into an invalid plan. It make sense though, to have an additional safety check in
the `DataSetJoin`. However, this check should be done in the constructor and not in the `translateToPlan()`
method (see FLINK-5547) to fail fast if a rule tries to create an invalid plan.


> Disable outer joins with non-equality predicates
> ------------------------------------------------
>
>                 Key: FLINK-5520
>                 URL: https://issues.apache.org/jira/browse/FLINK-5520
>             Project: Flink
>          Issue Type: Bug
>          Components: Table API & SQL
>    Affects Versions: 1.2.0
>            Reporter: Fabian Hueske
>            Assignee: lincoln.lee
>            Priority: Blocker
>             Fix For: 1.2.0
>
>
> Outer joins with non-equality predicates (and at least one equality predicate) compute
incorrect results. 
> Since this is not a very common requirement, I propose to disable this feature for the
1.2.0 release and correctly implement it for a later version.
> The fix should add checks in the Table API validation phase (to get a good error message)
and in the DataSetJoinRule to prevent translation of SQL queries with non-equality predicates
on outer joins.



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