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https://issues.apache.org/jira/browse/HIVE-14002?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15331503#comment-15331503
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Jesus Camacho Rodriguez commented on HIVE-14002:
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Thanks for reviewing [~ashutoshc]. In fact, _operator.acceptLimitPushdown()_ is
used to bail out if the operator does not accept the limit pushdown. This is
the same logic that was used for pushing it from the Limit operator, thus I
would expect that it is sound.
Further, if we cannot backtrack a column from the top RS to the bottom RS, we
bail out too (in fact, the new _checkKeys_ method does that).
> Extend limit propagation to subsequent RS operators
> ---------------------------------------------------
>
> Key: HIVE-14002
> URL: https://issues.apache.org/jira/browse/HIVE-14002
> Project: Hive
> Issue Type: Improvement
> Components: Physical Optimizer
> Affects Versions: 2.2.0
> Reporter: Nita Dembla
> Assignee: Jesus Camacho Rodriguez
> Attachments: HIVE-14002.patch
>
>
> In some occasions, for instance when RS dedup does not kick in, it is useful
> to propagate the limit to subsequent RS operators, as this will reduce
> intermediary results and impact performance. This issue covers that extension.
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