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A new lock manager has also been added to Hive, the DbLockManager.  This lock manager stores all lock information in the metastore.  In addition all transactions are stored in the metastore.  This means that transactions and locks are durable in the face of server failure.  To avoid clients dying and leaving transaction or locks dangling, a heartbeat is sent from lock holders and transaction initiators to the metastore on a regular basis.  If a heartbeat is not received in the configured amount of time, the lock or transaction will be aborted.

More details on locks used by this Lock Manager.

Configuration

These configuration parameters must be set appropriately to turn on transaction support in Hive:

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