[jira] [Commented] (PHOENIX-6412) Consider batching uncovered column merge for local indexes

["Kadir OZDEMIR (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/PHOENIX-6412?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17521971#comment-17521971 ] 

Kadir OZDEMIR commented on PHOENIX-6412:
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[~larsh] This is a dup of PHOENIX-6663. I think we can close this.

> Consider batching uncovered column merge for local indexes
> ----------------------------------------------------------
>
>                 Key: PHOENIX-6412
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-6412
>             Project: Phoenix
>          Issue Type: Improvement
>            Reporter: Lars Hofhansl
>            Priority: Minor
>             Fix For: 5.2.0
>
>         Attachments: 6412-hack.txt
>
>
> Currently uncovered columns are merged row-by-row, performing a Get to the data region for each matching row in the index region.
> Each Get needs to seek all the store scanners, and doing this per row is quite expensive.
> Instead we could batch inside the RegionScannerFactory.getWrappedScanner() -> RegionScanner.nextRaw() method. Collect N index rows and then execute a single skip scan on the data region. 
> I might be able to get to that, but there's someone who is interested in taking this up I would not mind :)



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