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From "Jesus Camacho Rodriguez (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-12543) Disable Hive ConstantPropagate optimizer when CBO has optimized the plan
Date Mon, 01 Feb 2016 11:32:39 GMT

    [ https://issues.apache.org/jira/browse/HIVE-12543?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15126145#comment-15126145
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Jesus Camacho Rodriguez commented on HIVE-12543:
------------------------------------------------

Thanks once again for checking in detail [~ashutoshc]. Below you can see comments on each
case:

- _join42.q : seems like we are not able to merge joins_ Join on constant values became cartesian
products, as we were joining on constant values. Currently Hive does not merge cartesian products.
I do not know if it would make sense to provide this kind of optimization (as Calcite produces
these plans)? Or maybe in some cases we would not want to merge them...? In any case, change
in the plan is correct. If we decide we should provide merge on cartesian product, we could
create a follow-up JIRA.

- _ppd_outer_join5.q : seems like we are not able to merge joins_ Same as above.

- _ppd_union_view.q : not fully propagating constant_ In fact, table is partitioned by _ds_
and partition pruning is kicking in. Thus, it is not necessary to replace the column value
for _ds_, as we know the column carries that value forward.

- _llap/dynamic_partition_pruning.q : DPP trigered - not sure if test was written to have
DPP or not._ This is a good catch. At first I thought it was good that DPP was kicking in.
However, after checking carefully, it does not make sense that DPP is kicking in for this
case, as static partition pruning is already being performed. Recognition for this case in
DPP should be enhanced so the optimization does not kick in. I think this is an orthogonal
issue, so I could create a follow-up JIRA for it once the patch goes in. What do you think?

Thanks

> Disable Hive ConstantPropagate optimizer when CBO has optimized the plan
> ------------------------------------------------------------------------
>
>                 Key: HIVE-12543
>                 URL: https://issues.apache.org/jira/browse/HIVE-12543
>             Project: Hive
>          Issue Type: Sub-task
>          Components: CBO, Logical Optimizer
>    Affects Versions: 2.0.0
>            Reporter: Jesus Camacho Rodriguez
>            Assignee: Jesus Camacho Rodriguez
>         Attachments: HIVE-12543.01.patch, HIVE-12543.02.patch, HIVE-12543.03.patch, HIVE-12543.04.patch,
HIVE-12543.patch
>
>




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