Managing Impala

Starting/Stopping Impala

You must start the statestore service before you start the catalog or the Impala service.

To start the Impala statestore and catalog services from the Control System, complete the following steps:

1. In the Navigation pane, expand the Cluster Views pane and click Dashboard.
2. In the Services pane, click Impala statestore. The Nodes screen appears and displays the node configured with the statestore service.
3. Click the hostname of the node with the statestore and catalog services configured to display the Node Properties screen.
4. Use the Stop/Start button in the Impala statestore row under Manage Services to start Impala statestore.
5. Use the Stop/Start button in the Impala catalog row under Manage Services to start Impala catalog.

To start Impala server from the Control System, complete the following steps:

1. In the Navigation pane, expand the Cluster Views pane and click Dashboard.
2. In the Services pane, click Impala server. The Nodes screen appears and displays the nodes configured with the Impala server.
3. Click the hostname of the a node with the Impala server configured to display its Node Properties screen.
4. Use the Stop/Start button in the Impala server row under Manage Services to start the Impala server.
5. Repeat steps 3 and 4 for the remaining nodes configured with the Impala server.

From the CLI

You must start the statestore service before you start the catalog or the Impala service.

To start Impala from the command line, complete the following steps:

1. Issue the following command to start the statestore service on the node with statestored:

   $ sudo maprcli node services -name impalastore -action start|stop -nodes <node IP addresses separated by a space>
   Example:
   $ sudo maprcli node services -name impalastore -action start -nodes 10.10.30.166

2. Issue the following command to start the catalog service on the node with catalogd:

   $ sudo maprcli node services -name impalacatalog -action start|stop -nodes <node IP addresses separated by a space>
   Example:
   $ sudo maprcli node services -name impalacatalog -action start -nodes 10.10.30.166

3. Issue the following command to start the Impala service on the node(s) with impalad:

   $ sudo maprcli node services -name impalaserver -action start|stop -nodes < node IP addresses separated by a space >
   Example:
   $ sudo maprcli node services -name impalaserver -action start -nodes 10.10.30.166

4. Optionally, you can run the following command to launch the impala-shell if you want to issue queries from the command line:

   ${IMPALA_HOME}/bin/impala-shell.sh

Modify Resource Allocation

If you run Impala on nodes that also run MapReduce, both frameworks may suffer poor performance if they have to compete for resources. You can configure memory based on your job requirements and SLAs to ensure that each framework has enough resources to avoid conflicts. For information about modifying memory, refer to Additional Impala Configuration Options.

Impala Logs

Impala logs provide information errors, configuration, and completed jobs. You can review log files on each node. An Impala administrator should review the log files and set log levels.

Impala uses the glog_v logging system to store information. Some messages refer to C++ file names. The GLOG_v environment variable specifies which types of messages Impala logs.

Reviewing Logs

You can locate log files in the Impala installation directory (/opt/mapr/impala/impala-<version>/logs) on each node with Impala. Impala creates a new set of log files on each statestored or impalad restart.

The following table provides a list of the important log files for the impalad and statestored processes with descriptions:

Setting Log Levels

The GLOG system has three logging levels that you can adjust by exporting variable settings. The logging levels are cumulative. Increasing logging levels may decrease performance and increases log size. Change logging settings before you start impalad.

The following table provides the logging levels and their descriptions:

Use the following command to change logging settings:

export GLOG_v=1

For more information on how to configure GLOG, including how to set variable logging levels for different system components, see Fixed in 5.2 r1.0.

Log Rotation