[
https://issues.apache.org/jira/browse/CALCITE-2573?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16621295#comment-16621295
]
Julian Hyde commented on CALCITE-2573:
--------------------------------------
I believe that the semantics of {{unknownAsFalse}} mode are that if the
expression returns UNKNOWN the simplified expression MAY instead return FALSE.
MAY, not MUST.
Rationale: this allows us to reduce the complexity of expressions to be used in
WHERE, HAVING, ON and FILTER clauses because we know that they treat the two
return values the same.
If so, it's OK for the simplifier to keep UNKNOWN as UNKNOWN.
> RexSimplify: simplify NULL to FALSE in uknownAsFalse mode
> ---------------------------------------------------------
>
> Key: CALCITE-2573
> URL: https://issues.apache.org/jira/browse/CALCITE-2573
> Project: Calcite
> Issue Type: Bug
> Components: core
> Affects Versions: 1.17.0
> Reporter: Vladimir Sitnikov
> Assignee: Julian Hyde
> Priority: Major
> Labels: newbie
>
> {noformat}2018-09-19 20:42:41,804 [pool-1-thread-1] INFO - Randomized test
> identified a potential defect. Feel free to fix that issue
> java.lang.AssertionError: result mismatch: when applied to {}, null yielded
> NULL, and false yielded false
> at org.apache.calcite.rex.RexSimplify.verify(RexSimplify.java:1208)
> at org.apache.calcite.rex.RexSimplify.simplify(RexSimplify.java:178)
> at
> org.apache.calcite.test.fuzzer.RexProgramFuzzyTest.checkTrueFalse(RexProgramFuzzyTest.java:169)
> at
> org.apache.calcite.test.fuzzer.RexProgramFuzzyTest.checkTrueFalse(RexProgramFuzzyTest.java:160)
> Suppressed: org.apache.calcite.test.fuzzer.RexProgramFuzzyTest$1: seed
> -4383181468718104148{noformat}
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
