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https://issues.apache.org/jira/browse/FLINK-2107?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14959088#comment-14959088
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Fabian Hueske commented on FLINK-2107:
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No problem. :-)
I will not solve all aspects, just the "easy" special cases.
For the remaining cases, we need a special hash table implementation that
allows to read all records from the hash table that have not been accessed
during the probe phase.
If you are interested, you can continue to work on these cases.
> Implement Hash Outer Join algorithm
> -----------------------------------
>
> Key: FLINK-2107
> URL: https://issues.apache.org/jira/browse/FLINK-2107
> Project: Flink
> Issue Type: New Feature
> Components: Local Runtime
> Reporter: Fabian Hueske
> Assignee: Chiwan Park
> Priority: Minor
> Fix For: pre-apache
>
>
> Flink does not natively support outer joins at the moment.
> This issue proposes to implement a hash outer join algorithm that can cover
> left and right outer joins.
> The implementation can be based on the regular hash join iterators (for
> example `ReusingBuildFirstHashMatchIterator` and
> `NonReusingBuildFirstHashMatchIterator`, see also `MatchDriver` class)
> The Reusing and NonReusing variants differ in whether object instances are
> reused or new objects are created. I would start with the NonReusing variant
> which is safer from a user's point of view and should also be easier to
> implement.
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