Ian Bertolacci developed LogicalRepeatUnion support within the apache/calcite repository, focusing on enhancing the RelHomogeneousShuttle component to correctly traverse and process recursive union operations in relational algebra trees. He introduced a new visit method in Java, enabling more robust handling of complex recursive queries and improving the reliability of query planning. To ensure correctness, Ian created comprehensive unit tests that validate the new logic’s behavior. His work demonstrated a strong grasp of Core Java, relational algebra, and test-driven development, resulting in a maintainable solution that reduces the risk of incorrect query plans for recursive union scenarios in Calcite.