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https://issues.apache.org/jira/browse/CALCITE-2973?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16808324#comment-16808324
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Lai Zhou commented on CALCITE-2973:
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[~julianhyde],[~zabetak] , good idea.
I just create a new rule for my application, to avoid changing the
calcite-core.
I'll make a PR later to allow theta joins to be executed using a merge join or
hash join.
I draw a table to describe the relationship of join types and join operators：
|| ||inner||non-inner||
|*only equi condition*|EnumerableJoin|EnumerableJoin|
|*only* *non-equi condition*** ** |EnumerableJoin|EnumerableThetaJoin|
|*mixed equi and non-equi condition*|EnumerableJoin+EnumerableFilter
or
EnumerableMergeJoin(changed)
|EnumerableThetaJoin
or
EnumerableMergeJoin
or
EnumerableHashJoin|
If a join is non-inner and has ** equi and non-equi condition meanwhile, we
have 3 choice to plan it.
Now EnumerableThetaJoin and EnumerableMergeJoin have a corresponding rule
respectively，
What do you think if I introduce a new rule( EnumerableThetaHashJoinRule) to
allow theta joins to be executed using a hash join？
> Allow theta joins to be executed using a merge join algorithm
> -------------------------------------------------------------
>
> Key: CALCITE-2973
> URL: https://issues.apache.org/jira/browse/CALCITE-2973
> Project: Calcite
> Issue Type: New Feature
> Components: core
> Affects Versions: 1.19.0
> Reporter: Lai Zhou
> Priority: Minor
>
> Now the EnumerableMergeJoinRule only supports an inner and equi join.
> If users make a theta-join query for a large dataset (such as 10000*10000),
> the nested-loop join process will take dozens of time than the sort-merge
> join process .
> So if we can apply merge-join or hash-join rule for a theta join, it will
> improve the performance greatly.
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