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https://issues.apache.org/jira/browse/HIVE-14431?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15992822#comment-15992822
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Remus Rusanu edited comment on HIVE-14431 at 5/2/17 12:48 PM:
--------------------------------------------------------------
Not all changes are in RexSimplify. The 3rd case you added
{code}
+ // 3) Another simplification
+ // CASE
+ // WHEN p1 THEN x
+ // WHEN p2 THEN y
+ // ELSE TRUE
+ // END
{code}
is not currently in Calcite. I made the changes in Hive, but the CASE is left
as a CASE, not transformed into an OR.
was (Author: rusanu):
@jcamachorodriguez Not all changes are in RexSimplify. The 3rd case you added
{code}
+ // 3) Another simplification
+ // CASE
+ // WHEN p1 THEN x
+ // WHEN p2 THEN y
+ // ELSE TRUE
+ // END
{code}
is not currently in Calcite. I made the changes in Hive, but the CASE is left
as a CASE, not transformed into an OR.
> Recognize COALESCE as CASE
> --------------------------
>
> Key: HIVE-14431
> URL: https://issues.apache.org/jira/browse/HIVE-14431
> Project: Hive
> Issue Type: Improvement
> Components: CBO
> Affects Versions: 2.2.0
> Reporter: Jesus Camacho Rodriguez
> Assignee: Remus Rusanu
> Attachments: HIVE-14431.01.patch, HIVE-14431.03.patch,
> HIVE-14431.2.patch, HIVE-14431.patch
>
>
> Transform:
> {code}
> (COALESCE(a, '') = '') OR
> (a = 'A' AND b = c) OR
> (a = 'B' AND b = d) OR
> (a = 'C' AND b = e) OR
> (a = 'D' AND b = f) OR
> (a = 'E' AND b = g) OR
> (a = 'F' AND b = h)
> {code}
> into:
> {code}
> (a='') OR
> (a is null) OR
> (a = 'A' AND b = c) OR
> (a = 'B' AND b = d) OR
> (a = 'C' AND b = e) OR
> (a = 'D' AND b = f) OR
> (a = 'E' AND b = g) OR
> (a = 'F' AND b = h)
> {code}
> With complex queries, this will lead us to factor more predicates that could
> be pushed to the TS.
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