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https://issues.apache.org/jira/browse/HIVE-14362?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15433811#comment-15433811
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Gopal V commented on HIVE-14362:
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bq. I assume that your major concern is performance difference, rather than
functional, right?
[~pxiong]: Ran through my perf tests last night and this patch is nearly free -
because there's no branch or virtual calls, the incq instruction doesn't have a
CPU stall associated with it and is pretty much running with no additional perf
impact (nothing measurable). No perf concerns for this impl - the closeOp() is
not a hot function, so it doesn't matter unless a user is explicitly running
"explain analyze".
> Support explain analyze in Hive
> -------------------------------
>
> Key: HIVE-14362
> URL: https://issues.apache.org/jira/browse/HIVE-14362
> Project: Hive
> Issue Type: New Feature
> Reporter: Pengcheng Xiong
> Assignee: Pengcheng Xiong
> Attachments: HIVE-14362.01.patch, HIVE-14362.02.patch,
> compare_on_cluster.pdf
>
>
> Right now all the explain levels only support stats before query runs. We
> would like to have an explain analyze similar to Postgres for real stats
> after query runs. This will help to identify the major gap between
> estimated/real stats and make not only query optimization better but also
> query performance debugging easier.
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