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From "Thomas Tauber-Marshall (Code Review)" <ger...@cloudera.org>
Subject [Impala-ASF-CR] IMPALA-1861: Simplify conditionals with constant conditions
Date Thu, 12 Jan 2017 19:57:06 GMT
Thomas Tauber-Marshall has posted comments on this change.

Change subject: IMPALA-1861: Simplify conditionals with constant conditions
......................................................................


Patch Set 8:

(4 comments)

http://gerrit.cloudera.org:8080/#/c/5585/7/fe/src/main/java/org/apache/impala/rewrite/SimplifyConditionalsRule.java
File fe/src/main/java/org/apache/impala/rewrite/SimplifyConditionalsRule.java:

Line 154:     // Contains all 'when' clauses with non-constant conditions, used to construct
the new
> construct
Done


Line 157:     // Set to THEN of first constant TRUE clause, if any.
> comment: first constant true when clause
Done


Line 188:         } else {
> this can be misread to apply to the following else if
Done


Line 189:           // This WHEN is always FALSE, so it can be removed.
> can whenExpr be a null literal, given l160?
You're right - I was thinking of the hasCaseExpr case where whenExpr comes from the BinaryPredicate
we construct and constant fold above, but I don't guess there's any expression of the form
"non-null literal = non-null literal" that would constant fold down to NULL.


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Gerrit-MessageType: comment
Gerrit-Change-Id: Id70aaf9fd99f64bd98175b7e2dbba28f350e7d3b
Gerrit-PatchSet: 8
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Thomas Tauber-Marshall <tmarshall@cloudera.com>
Gerrit-Reviewer: Alex Behm <alex.behm@cloudera.com>
Gerrit-Reviewer: Bharath Vissapragada <bharathv@cloudera.com>
Gerrit-Reviewer: Marcel Kornacker <marcel@cloudera.com>
Gerrit-Reviewer: Thomas Tauber-Marshall <tmarshall@cloudera.com>
Gerrit-Reviewer: Tim Armstrong <tarmstrong@cloudera.com>
Gerrit-HasComments: Yes

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