Worked on the simplex-chat/simplex-chat repository to address a critical issue in delivery tracking within a PostgreSQL environment. Focused on database optimization, the developer identified and resolved a bug where the delivery cursor failed to advance to the maximum group member ID, which could lead to misordered deliveries and inconsistent analytics. By introducing an ORDER BY clause to the relevant SQL query, the fix ensured group members were processed in ascending ID order, improving both reliability and accuracy of delivery tracking. This work demonstrated strong skills in PostgreSQL and Haskell, emphasizing careful debugging and targeted, low-risk code changes for production systems.