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https://issues.apache.org/jira/browse/HIVE-20491?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16603259#comment-16603259
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Zoltan Haindrich edited comment on HIVE-20491 at 9/4/18 4:13 PM:
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[~ashutoshc] yes; I was planning to do that - right now this patch only fixes
the estimations; and sets the most conservative estimate(fast3) by default.
I'm still working on deciding and forwarding that decision...right now I think
that will not be in this patch....
was (Author: kgyrtkirk):
yes; I was planning to do that - right now this patch only fixes the
estimations; and sets the most conservative estimate(fast3) by default.
I'm still working on deciding and forwarding that decision...right now I think
that will not be in this patch....
> Fix mapjoin size estimations for Fast implementation
> ----------------------------------------------------
>
> Key: HIVE-20491
> URL: https://issues.apache.org/jira/browse/HIVE-20491
> Project: Hive
> Issue Type: Improvement
> Components: Statistics
> Reporter: Zoltan Haindrich
> Assignee: Zoltan Haindrich
> Priority: Major
> Attachments: HIVE-20491.01.patch, HIVE-20491.01wip02.patch,
> HIVE-20491.02.patch
>
>
> HIVE-19824 have fixed the estimations; but it calculated for the "optimized"
> impl; the "fast" one has a little bit bigger footprint.
> It also seems like fast is a bit overestimated at runtime...that should be
> also taken care of.
> | numkeys | implementation | compiler estimation | runtime estimation |
> runtime measurement | ce / rm | re / rm |
> | 25M | FAST | 1168435456 | 2189433712 | 1513584984 | .77 | 1.44 |
> | 25M | OPTIMIZED | 1168435456 | 1191203764 | 1168439664 | 100% | 1.01 |
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