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https://issues.apache.org/jira/browse/HIVE-23006?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Panagiotis Garefalakis updated HIVE-23006:
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Status: Open (was: Patch Available)
> Compiler support for Probe MapJoin
> ----------------------------------
>
> Key: HIVE-23006
> URL: https://issues.apache.org/jira/browse/HIVE-23006
> Project: Hive
> Issue Type: Sub-task
> Reporter: Panagiotis Garefalakis
> Assignee: Panagiotis Garefalakis
> Priority: Major
> Labels: pull-request-available
> Attachments: HIVE-23006.01.patch
>
> Time Spent: 1h 40m
> Remaining Estimate: 0h
>
> The decision of pushing down information to the Record reader (potentially
> reducing decoding time by row-level filtering) should be done at query
> compilation time.
> This patch adds an extra optimisation step with the goal of finding Table
> Scan operators that could reduce the number of rows decoded at runtime using
> extra available information.
> It currently looks for all the available MapJoin operators that could use the
> smaller HashTable on the probing side (where TS is) to filter-out rows that
> would never match.
> To do so the HashTable information is pushed down to the TS properties and
> then propagated as part of MapWork.
> If the a single TS is used by multiple operators (shared-word), this rule can
> not be applied.
> This rule can be extended to support static filter expressions like:
> _select * from sales where sold_state = 'PR';_
> This optimisation manly targets the Tez execution engine running on Llap.
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