Cloudera Docs

Stopping Impala

Explains how to gracefully shut down Impala Daemons by first allowing running queries a specified amount of time to complete the process.

The flow to gracefully shut down an Impala Daemon is as follows:
  1. The shutdown is initiated.
  2. The grace period starts. The Impala Daemon informs other coordinators not to schedule any new queries on it. This allows queries already scheduled to run on this daemon by other coordinators to start executing.
  3. The grace period expires.
  4. The Impala Daemon continuously checks if there are no queries or fragments running.
  5. If there are no queries or fragments running, it shuts down.
  6. Otherwise, when it reaches the IMPALA_GRACEFUL_SHUTDOWN_DEADLINE duration, Impala Daemon shuts down.

Once Cloudera Manager initiates the stop/shutdown command, the Impala Daemon starts up the graceful shutdown process, and the process cannot be reverted. However, if you need to change the hard deadline in Cloudera Manager, you can cancel the shutdown command, change the Impala Daemon Graceful Shutdown, and start the shutdown command again.

  1. Optionally, set the grace period.
    1. In Cloudera Manager, navigate to Impala Service > Configuration > Scope > Impala Daemon.
    2. In the Impala Daemon Command Line Argument Advanced Configuration Snippet (Safety Valve) field, specify the grace period:

      --shutdown_grace_period_s=<new grace period in seconds>

      The default grace period is 2 minutes.
      It is strongly recommended that you use the default value and not change the setting.
  2. Optionally, set the hard deadline after which Impala is shut down regardless of whether queries are still running on it.
    1. In Cloudera Manager, navigate to Impala Service > Configuration > Scope > Impala Daemon.
    2. In the Impala Graceful Shutdown Deadline field, specify the time to wait for running queries.
      The default is 60 minutes.
      If you specify 0, Impala will shutdown immediately without waiting for running queries
  3. In Cloudera Manager, navigate to Impala Service > Instances.
  4. Click an Impala Daemon role.
  5. Click Actions > Impala Daemon Graceful Shutdown.