[jira] [Created] (FLINK-22113) UniqueKey constraint is lost with multiple sources join in SQL

[Shang Yuanchun (Jira)]

Fu Kai created FLINK-22113:
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             Summary: UniqueKey constraint is lost with multiple sources join in SQL
                 Key: FLINK-22113
                 URL: https://issues.apache.org/jira/browse/FLINK-22113
             Project: Flink
          Issue Type: Bug
          Components: Table SQL / Planner
    Affects Versions: 1.13.0
            Reporter: Fu Kai


Hi team,
 
We have a use case to join multiple data sources to generate a continuous updated view. We defined primary key constraint on all the input sources and all the keys are the subsets in the join condition. All joins are left join.
 
In our case, the first two inputs can produce *JoinKeyContainsUniqueKey* input sepc, which is good and performant. While when it comes to the third input source, it's joined with the intermediate output table of the first two input tables, and the intermediate table does not carry key constraint information(although the thrid source input table does), so it results in a *NoUniqueKey* input sepc. Given NoUniqueKey inputs has dramatic performance implications per the[ Force Join Unique Key|http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/Force-Join-Unique-Key-td39521.html#a39651] email thread, we want to know if there is any mitigation solution for this.
 



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