Worked on the mmoayyed/cas repository to optimize principal-based session retrieval in the MongoDB ticket registry. Addressed performance bottlenecks by replacing an expensive text index search with a direct IDX_PRINCIPAL index lookup for the getSessionsFor(principalId) operation, which reduced query latency and resource usage. Removed the obsolete JSON text index to simplify database maintenance and indexing. Developed targeted tests to verify both retrieval and deletion of sessions for a given principal, enhancing reliability and regression coverage. Utilized Java for backend development, focusing on database management, MongoDB optimization, and comprehensive testing to improve maintainability and lay groundwork for future enhancements.