hue connection failure Hive has been using ZooKeeper as distributed lock manager to support concurrency in HiveServer2. The ZooKeeper-based lock manager works fine in a small scale environment. However, as more and more users move to HiveServer2 from HiveServer and start to create a large number of concurrent sessions, problems can arise. The major problem is that the number of open connections between Hiveserver2 and ZooKeeper keeps rising until the connection limit is hit from the ZooKeeper server side. At that point, ZooKeeper starts rejecting new connections, and all ZooKeeper-dependent flows become unusable. Several Hive JIRAs (such as HIVE-4132, HIVE-5853 and HIVE-8135 etc.) have been opened to address this problem, and it recently got fixed through HIVE-9119.