Hi Calcite community, I'm running into some challenges using SubqueryRemoveRule and was hoping the community could help me understand any gaps in my understanding.
I am attempting to remove subqueries from row expressions in a relational plan. My motivation for doing this is that I want to call metadata queries such GetColumnOrigins on my relational plan, but these tools don't seem to work unless subqueries are removed. To remove subqueries, I am... - Using SqlToRelConverter to convert from SqlNode to RelRoot. - After obtaining the RelRoot, using a HepProgram with subquery remove rules to remove the subqueries. For small programs, this process works fine, however when testing against larger queries, ~2MB, the process of removing subqueries takes about as much time as converting a SqlNode to a RelRoot, effectively doubling the time to analyze a query. I've tried using a deprecated setting, SqlToRelConverter.Config.isExpand, which seems to provide results similar to what I want with minimal performance impact. Since SqlToRelConverter.Config.isExpand is deprecated, I assume that the non-deprecated way to expand subqueries would be as performant or better, but I am experiencing a worse performance. This leads me to believe that I'm using the APIs incorrectly, but I'm not sure what I am missing. Q: Is there a more efficient way in Calcite to remove subqueries than what I've described above? Is there risk to using SqlToRelConverter.Config.isExpand even if it's deprecated? Q: Are there any other resources besides Java docs and GitHub projects I could refer to to learn more about my problem? Thanks for any help, Logan
