You can modify the
env.sh file located in
/opt/mapr/impala/impala-<version>/conf/ to set certain Impala start up options.
Modifying Start Up Options
env.sh file contains values that the Impala server, statestore, and catalog services use during start up. The file also has information about resources allocated for Impala. Most of the default values in the
env.sh file should work effectively, however there are some values that you can modify. You can check the current value of all the settings through the Impala web interface, available by default at http://<impala-node-hostname>:25000/varz.
You may want to modify the following content in the
- Statestore address
- Amount of memory available to Impala
- Core dump enablement
- Session and query idle time
To modify the values, edit the
env.sh file and then restart the Impala server, Impala statestore, and Impala catalog to implement the changes.
Example of some file content that you may want to modify:
The following table contains a list of settings that you can edit in
/opt/mapr/impala/impala-<version>/conf/env.sh with descriptions for how to change them:
You can modify this setting to change the statestore IP address or hostname.
If you run Impala on nodes that also run MapReduce, both frameworks may compete for memory. Configure memory based on your job requirements and SLAs to ensure that each framework has enough memory to avoid conflicts.
You can include the
You can also include the
To limit Impala to 50% of system memory, modify:
Core dump enablement
Core dump file locations can vary depending on your operating system configuration. Other security settings may prevent Impala from writing core dumps when you enable this option.
To enable core dumps, change the following:
|Session and query idle time|
You can modify the time for which sessions and queries can remain idle by adding the following options to
-idle_query_timeout=<value in seconds> \
-idle_session_timeout=<value in seconds> \
|Use background threads to load|
and cache metadata
The following option controls the parallelism of metadata loading during start up for the catalogd daemon and makes Impala use background threads after start up to load and cache metadata.
The default setting is
|Determine how much parallelism Impala devotes to loading metadata in background|
The following option controls the parallelism of metadata loading during start up for the catalogd daemon and determines how much parallelism Impala devotes to loading metadata in the background:
The default is 16, but you can increase this value for systems with a huge number of databases, tables, or partitions. You can lower this value for busy systems that have CPU-constraints due to jobs from other components running in the cluster.
|INSERT to create new partition |
and inherit permissions
The following option causes Impala INSERT statements to create each new partition with the same MapR-FS permissions as its parent directory:
By default, INSERT statements create directories for new partitions using default MapR-FS permissions.
After you edit
/opt/mapr/impala/impala-<version>/conf/env.sh, use the following commands to restart the Impala server and services:
Issue the following command to restart the Impala server:
Issue the following command to restart the Impala statestore:
Issue the following command to restart the Impala catalog: