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From "Anton Kedin (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (BEAM-3345) [SQL] Reject Unsupported Joins
Date Wed, 13 Dec 2017 22:38:00 GMT

     [ https://issues.apache.org/jira/browse/BEAM-3345?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Anton Kedin updated BEAM-3345:
------------------------------
    Description: 
Related to https://issues.apache.org/jira/browse/BEAM-3190 .

We don't know what meaningful join semantics is, in presence of multiple trigger firings.
I.e. in accumulating mode it will result in multiple duplicated join results, and in discarding
mode it will only join deltas, both of these scenarios seem to be super subtle and can lead
to misunderstanding and misuse by the end users.

Until we have a way to implement a correct join semantics (e.g. using retraction) we should
reject unsupported window/trigger combinations. 

  was:
Related to https://issues.apache.org/jira/browse/BEAM-3190 .

We don't know what meaningful join semantics in presence of multiple trigger firings. I.e.
in accumulating mode it will result in multiple duplicated join results, and in discarding
mode it will only join deltas, both of these scenarios seem to be super subtle and can lead
to misunderstanding and misuse by the end users.

Until we have a way to implement a correct join semantics (e.g. using retraction) we should
reject unsupported window/trigger combinations. 


> [SQL] Reject Unsupported Joins
> ------------------------------
>
>                 Key: BEAM-3345
>                 URL: https://issues.apache.org/jira/browse/BEAM-3345
>             Project: Beam
>          Issue Type: Bug
>          Components: dsl-sql
>            Reporter: Anton Kedin
>            Assignee: Xu Mingmin
>
> Related to https://issues.apache.org/jira/browse/BEAM-3190 .
> We don't know what meaningful join semantics is, in presence of multiple trigger firings.
I.e. in accumulating mode it will result in multiple duplicated join results, and in discarding
mode it will only join deltas, both of these scenarios seem to be super subtle and can lead
to misunderstanding and misuse by the end users.
> Until we have a way to implement a correct join semantics (e.g. using retraction) we
should reject unsupported window/trigger combinations. 



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