Hello Matthew Jacobs,
I'd like you to reexamine a change. Please visit
http://gerrit.cloudera.org:8080/7829
to look at the new patch set (#4).
Change subject: IMPALA-5211: Simplifying conditionals (istrue, nullif, etc.)
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IMPALA-5211: Simplifying conditionals (istrue, nullif, etc.)
This commit simplifies the following conditional functions:
* istrue
* isfalse
* isnottrue
* isnotfalse
* zeroifnull
* nullifzero
* nullvalue
* nonnullvalue
* nullif
Most of these simplifications work when the arguments to
these functions are literals. The one exception is
that nullif(x, y) simplifies to NULL when x.equals(y)
as expressions. This is valid since nullif(null, null)=null.
This simplification has not been applied to the equivalent
"case x=x then null else null".
In terms of the implementation is a bit of a toss-up between re-writing
these into their equivalent case statements or simplifying them here.
Testing:
* Added new tests to ExprRewriteRulesTest
* Confirmed (using EclEmma, which uses jococo engine) that coverage is
good.
Change-Id: Id91ca968a0c0be44e1ec54ad8602f91a5cb2e0e5
---
M fe/src/main/java/org/apache/impala/rewrite/SimplifyConditionalsRule.java
M fe/src/test/java/org/apache/impala/analysis/ExprRewriteRulesTest.java
2 files changed, 208 insertions(+), 18 deletions(-)
git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/29/7829/4
--
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Gerrit-MessageType: newpatchset
Gerrit-Change-Id: Id91ca968a0c0be44e1ec54ad8602f91a5cb2e0e5
Gerrit-PatchSet: 4
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Philip Zeyliger <[email protected]>
Gerrit-Reviewer: Alex Behm <[email protected]>
Gerrit-Reviewer: Matthew Jacobs <[email protected]>
Gerrit-Reviewer: Philip Zeyliger <[email protected]>
