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https://issues.apache.org/jira/browse/FLINK-11425?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16754964#comment-16754964
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LiuJi commented on FLINK-11425:
-------------------------------

I am very glad to hear that, thanks very much! [~ykt836]

> Support of “Hash Teams” in Hybrid Hash Join
> -------------------------------------------
>
>                 Key: FLINK-11425
>                 URL: https://issues.apache.org/jira/browse/FLINK-11425
>             Project: Flink
>          Issue Type: New Feature
>          Components: Core, Optimizer
>            Reporter: LiuJi
>            Priority: Major
>
> Hybrid Hash Join is already supported in current version. The join starts 
> operating in memory and gradually starts spilling contents to disk, when the 
> memory is not sufficient.
>  
> Current hash join only support two inputs,  so when a job contains multiple 
> hash joins which have the same join keys, it will consume some unnecessary 
> resources (I/O, memory, etc) because some upstream output data may useless 
> for downstream hash join.
>  
> According to the above observations, we want to provide a HashTeamManager to 
> implement multiway inputs hash join by combining several two way hash join 
> which have same join keys. HashTeamManager manage the relations of multiple 
> HashTables and improve efficiency in memory use and lower I/O operations by 
> joining multiple relations at one time.



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