[
https://issues.apache.org/jira/browse/CALCITE-2451?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16622400#comment-16622400
]
Vladimir Sitnikov commented on CALCITE-2451:
--------------------------------------------
{quote}"x < NULL" was a 2-deep tree, now we match "(x < NULL) IS TRUE" which is
a 3-deep tree{quote}
Matching does not seem to be of a complicated problem to me.
What bothers me is cases like {{(x=2) AND (y=1)}} (assume x,y are nullable)
{{// AND(x, y) IS TRUE ==> x IS TRUE and y IS TRUE}}
{{isTrue( (x=2) AND (y=1) )}} ==> {{isTrue(x=2) AND isTrue(y=1)}}
If we stop here, the final expression turned out to me more complicated than
the original one (basically we added two isTrue nodes for little reasons).
We can unwrap like {{isTrue(x=2) AND isTrue(y=1)}} ==> {{isNotNull(x\) AND x=2
AND isNotNull(y\) AND y=1}}, however that is not much better than the original
code.
> RexSimplify: fuse unknownAsFalse and IS TRUE handling
> -----------------------------------------------------
>
> Key: CALCITE-2451
> URL: https://issues.apache.org/jira/browse/CALCITE-2451
> Project: Calcite
> Issue Type: Sub-task
> Components: core
> Affects Versions: 1.17.0
> Reporter: Vladimir Sitnikov
> Assignee: Julian Hyde
> Priority: Major
>
> It looks like {{unknownAsFalse}} duplicates {{IS_TRUE}} handling.
> In other words, {{withUnknownAsFalse(true). simplfy(expr)}} is more or less
> comparable to {{simplify(isTrue(expr))}}
> Implementing {{IS_TRUE/IS_FALSE/...}} simplification possibilities might make
> {{unknownAsFalse}} obsolete.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
