Kevin, thank you for devoting your time. I would like to integrate CALCITE-2817 (Make CannotPlanException great) although there are slight changes required. I wonder if https://issues.apache.org/jira/browse/CALCITE-2845 (Avatica duplicates exception messages) could/should be fixed in Avatica as well. Frankly speaking, I think "e.getMessage(), e)" pattern should (almost) never be used.
Vladimir
