In all versions of Hive-MR3:
- For HiveServer2 running in shared session mode, the user should terminate it manually in any of the following cases:
- The Yarn Application is killed.
- The DAGAppMaster is killed.
- The DAGAppMaster fails in the last attempt (after creating
Ideally HiveServer2 should terminate itself in such a case, but this is not implemented yet.
- When multiple TaskAttempts run inside a DAGAppMaster or in a ContainerWorker in Yarn mode, GroupByOperator correctly calculates neither the size of memory assigned to each TaskAttempt nor the size of memory used by a TaskAttempt. As a result, it is hard to predict when GroupByOperator flushes hash tables.
- When multiple TaskAttempts run inside a DAGAppMaster,
GroupByOperator conservatively estimates the size of memory used by a TaskAttempt.
As a result, GroupByOperator flushes hash tables more often than necessary.
The user can mitigate this issue by increasing the value for the configuration key
- Due to a critical bug introduced in Hive 2.3.2 (HIVE-18786), Hive-MR3 occasionally fails with NullPointerException when using windowing functions, especially if multiple queries are running concurrently.