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https://issues.apache.org/jira/browse/HIVE-10636?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14543221#comment-14543221
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Gopal V commented on HIVE-10636:
--------------------------------
[~ashutoshc]: +1 on the case rotation.
But it misses out on one of the CASE when folds, so HIVE-9644 wasn't
comprehensive for the NULL and TRUE branch cases.
{code}
hive> explain select count(1) from store_sales where (case ss_sold_date_sk when
2 then true else null end);
...
Vertices:
Map 1
Map Operator Tree:
TableScan
alias: store_sales
filterExpr: CASE (ss_sold_date_sk) WHEN (2) THEN (true) ELSE
(null) END (type: boolean)
{code}
the (true) / (null) WHEN is not getting folded, which is the last case (and the
very first).
Would be nice to get that one is as well (as well as the no-else, which
defaults to NULL).
{code}
hive> explain select count(1) from store_sales where (case ss_sold_date_sk when
2 then true end);
OK
...
Vertices:
Map 1
Map Operator Tree:
TableScan
alias: store_sales
filterExpr: CASE (ss_sold_date_sk) WHEN (2) THEN (true) END
(type: boolean)
{code}
Other than those two cases, everything seems to work fine.
> CASE comparison operator rotation optimization
> ----------------------------------------------
>
> Key: HIVE-10636
> URL: https://issues.apache.org/jira/browse/HIVE-10636
> Project: Hive
> Issue Type: New Feature
> Components: Logical Optimizer
> Affects Versions: 0.14.0, 1.0.0, 1.2.0, 1.1.0
> Reporter: Ashutosh Chauhan
> Assignee: Ashutosh Chauhan
> Attachments: HIVE-10636.1.patch, HIVE-10636.2.patch,
> HIVE-10636.3.patch, HIVE-10636.patch
>
>
> Step 1 as outlined in description of HIVE-9644
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