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Posted to issues@drill.apache.org by "Jacques Nadeau (JIRA)" <ji...@apache.org> on 2015/01/04 22:28:53 UTC

[jira] [Updated] (DRILL-351) MergeJoin physical operator projects columns that may not be needed

     [ https://issues.apache.org/jira/browse/DRILL-351?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jacques Nadeau updated DRILL-351:
---------------------------------
    Issue Type: Improvement  (was: Bug)

> MergeJoin physical operator projects columns that may not be needed
> -------------------------------------------------------------------
>
>                 Key: DRILL-351
>                 URL: https://issues.apache.org/jira/browse/DRILL-351
>             Project: Apache Drill
>          Issue Type: Improvement
>          Components: Execution - Operators
>            Reporter: Aman Sinha
>             Fix For: Future
>
>
> The MergeJoin physical operator currently projects all columns from the left and right inputs with the assumption that a subsequent Project will drop the unnecessary columns. This is sub-optimal because we incur the memory and cpu overhead of populating the output record batch value vectors for those columns. Ideally, the operator could keep track of the columns that are needed by the parent (downstream) operator and only project those  columns. 



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