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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:
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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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