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https://issues.apache.org/jira/browse/CALCITE-4705?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17564604#comment-17564604
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Haisheng Yuan commented on CALCITE-4705:
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I don't know any other databases that support skew join hint besides these two.
> Support hints like /*+ skewjoin(a(c0, c1)) */
> ---------------------------------------------
>
> Key: CALCITE-4705
> URL: https://issues.apache.org/jira/browse/CALCITE-4705
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Affects Versions: 1.27.0
> Reporter: jibiyr
> Assignee: jibiyr
> Priority: Minor
>
> Dear community,
> calcite parse support hint now,but it can not parse hint like follow,
> _*select /*+ skewjoin(a(c0, c1)) */ * from T0 a join T1 b on a.c0 = b.c0,*_
> this is the bnf which is calcite supported now,
> {code:java}
> //
> hint:
> hintName
> | hintName '(' hintOptions ')'
> hintOptions:
> hintKVOption [, hintKVOption ]*
> | optionName [, optionName ]*
> | optionValue [, optionValue ]*
> hintKVOption:
> optionName '=' stringLiteral
> | stringLiteral '=' stringLiteral
> optionValue:
> stringLiteral
> | numericLiteral
> {code}
> I think the hintOptions should support the expression pattern,like a(c0,c1).
> And this pattern can be parsed by spark/presto now.
>
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