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https://issues.apache.org/jira/browse/CALCITE-2838?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16767545#comment-16767545
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Julian Hyde commented on CALCITE-2838:
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bq. Make sure that there aren't a lot of changes happening for very little
purpose,
Sorry, I wasn't clear. The "changes" I am concerned about are not code changes
(e.g. PRs) but plan changes. I meant that if your change causes a lot of
changes to expected test output, or changes some of the assumptions that
simplifier is based on, then that would be undesirable.
Definitely keep CALCITE-2838 etc. as separate cases and PRs.
> Simplification: Remove redundant IS TRUE checks
> -----------------------------------------------
>
> Key: CALCITE-2838
> URL: https://issues.apache.org/jira/browse/CALCITE-2838
> Project: Calcite
> Issue Type: Improvement
> Reporter: Zoltan Haindrich
> Assignee: Zoltan Haindrich
> Priority: Blocker
> Fix For: 1.19.0
>
>
> In case simplifcation is already processing in unknownAsFalse mode, {{expr IS
> TRUE}} is redundant - and may just prevent further optimizations from
> happening:
> {code}
> @Test public void testRedundantIsTrue() {
> // in case of unknownAsFalse
> // x is TRUE <=> x
> checkSimplify3(isTrue(vBool(1)),
> "IS TRUE(?0.bool1)",
> "?0.bool1",
> "IS TRUE(?0.bool1)");
> }
> {code}
> there are some further possibilities
> {code}
> (unknownAsTrue) x is NOT FALSE <=> x
> (unknownAsTrue) x is FALSE <=> not x
> {code}
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