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Posted to issues@flink.apache.org by "Jark Wu (JIRA)" <ji...@apache.org> on 2019/06/26 08:14:00 UTC

[jira] [Closed] (FLINK-12971) Remove the constraint that lookup join needs a primary key or index key

     [ https://issues.apache.org/jira/browse/FLINK-12971?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jark Wu closed FLINK-12971.
---------------------------
       Resolution: Fixed
    Fix Version/s: 1.9.0

Fixed in 1.9.0: cb922bbfa0a26e147638d22aeceaf3e83b01e1d3

> Remove the constraint that lookup join needs a primary key or index key
> -----------------------------------------------------------------------
>
>                 Key: FLINK-12971
>                 URL: https://issues.apache.org/jira/browse/FLINK-12971
>             Project: Flink
>          Issue Type: Improvement
>          Components: Table SQL / Planner
>            Reporter: Jark Wu
>            Assignee: Jark Wu
>            Priority: Major
>              Labels: pull-request-available
>             Fix For: 1.9.0
>
>          Time Spent: 20m
>  Remaining Estimate: 0h
>
> Currently, we add a constraint in dimension table lookup join that the lookup fields must be a primary key or index key. This is not a logic constraint but a performance constraint. Because if there are no indexes on the lookup key, the lookup performance will be poor. 
> We will remove this constraint because not every table have a primary key or indexes (e.g. Hive tables). It's the user's responsibility if the lookup fields are not keys and get a bad performance. In this case, users should add indexes on these fields. In the future, we can also propagate out these tuning information before SQL is executed.



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