[ https://issues.apache.org/jira/browse/CALCITE-5639?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17711506#comment-17711506 ]
Julian Hyde commented on CALCITE-5639: -------------------------------------- It's quite possible that the Javadoc on {{class Strong}} is incorrect. The class is rather complicated, especially the reasoning about when an expression is "strong on" a particular input argument. That said, I think the implementation of the class is strong (pun intended), is well-supported by unit tests, and we should use the class more in {{RexSimplify}}. > RexSimplify should remove IS NOT NULL check when LIKE comparison is present > --------------------------------------------------------------------------- > > Key: CALCITE-5639 > URL: https://issues.apache.org/jira/browse/CALCITE-5639 > Project: Calcite > Issue Type: Bug > Affects Versions: 1.34.0 > Reporter: Leonid Chistov > Assignee: Leonid Chistov > Priority: Minor > Labels: pull-request-available > Time Spent: 20m > Remaining Estimate: 0h > > Consider query like > {code:java} > select r_reason_desc from reason > where r_reason_desc is not null and r_reason_desc like '%child%' > {code} > where "r_reason_desc" is a nullable field. > When RexSimplify::simplifyFilterPredicates is called on that conjunction of > expressions, expression is not simplified, meaning that redundant "is not > null" check is not removed. > In the same time, if query like > {code:java} > select r_reason_desc from reason > where r_reason_desc is not null and r_reason_desc >= 'A'{code} > is passed to optimizer, redundant "is not null" check is eliminated. -- This message was sent by Atlassian Jira (v8.20.10#820010)