[CALCITE-2888] Enhance RexImplicationChecker to better handle filters with CAST

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: core
• Labels: pull-request-available
• Assignee: Juhwan Kim
• Reporter: Juhwan Kim
• Created: 01/Mar/19 18:38
• Updated: 02/Mar/19 08:14

Description

I saw some cases where RexImplicationChecker gave an AssertionError when CAST was involved in the filters.

For example, if a filter is
'>(CAST(SOME_VHARCHAR_INPUT_REF, DATE), SOME_DATE_LITERAL)',
currently, it removes CAST first and tries to convert DATE literal to VARCHAR type,
which is not supported, and runtime AssertionError is thrown during implication checking.

I think the issue can be solved by using RexExecutor's reduce function before removing cast from literal side. Also, allowing other implementations of RexExecutor would make it more flexible. 

Issue Links

• links to: GitHub Pull Request #1081