Worked on the IBM/velox repository to enhance stability and correctness in plan node processing by addressing two critical bugs over a two-month period. Focused on C++ development, the work involved improving deserialization context propagation within nested ISerializable::deserialize calls, which strengthened the robustness of serialization and deserialization for complex plan node structures. Additionally, fixed incorrect aggregation logic in PlanNodeStats::operator+=, ensuring accurate statistics for cost-based optimization. Expanded test coverage by introducing targeted regression tests, reinforcing code quality and reliability. The contributions centered on C++, deserialization, and testing, directly supporting the reliability and maintainability of the Velox query engine codebase.