In December 2025, Ivan Sergeenko focused on maintaining test integrity and cost-model accuracy for the GreengageDB/greengage repository. He addressed a unit test issue by updating the Orca CCTETest cost model to reflect recent changes in hash join cost calculations, ensuring that test expectations matched the current system behavior. Working primarily with XML and leveraging his skills in cost modeling, data structures, and unit testing, Ivan’s targeted fix improved the reliability of performance assessments and contributed to stable continuous integration. His work enhanced code quality by aligning unit tests with production logic, supporting release readiness and reducing test flakiness.