During September 2025, Zhang Mingao focused on backend reliability within the apache/pulsar repository, addressing a critical configuration issue in Pulsar’s BookKeeper integration. He implemented a targeted fix to ensure the ZooKeeper timeout for the BookKeeper client was correctly set by propagating the metadataStoreSessionTimeoutMillis value from the broker configuration. This adjustment, developed using Java and properties files, resolved intermittent connection issues and improved cluster stability for BookKeeper-backed storage. Zhang’s work demonstrated a strong grasp of backend development and configuration management, delivering a robust solution that reduced operational risk and downtime for deployments relying on distributed storage coordination via ZooKeeper.