Cloudera Docs

Configuring the only coordinators request pool

Follow these steps to configure a coordinator-only request pool in Impala to optimize system table queries.

By configuring a coordinator-only request pool, you can run queries that do not require executors. This reduces resource usage and enhances system performance.

Ensure you have administrator access to modify Impala configurations.

  1. Log in to the Cloudera web interface and navigate to the Cloudera Data Warehouse service.
  2. In the Cloudera Data Warehouse service, click Virtual Warehouses in the left navigation panel.
  3. Select the Impala Virtual Warehouse, click options for the warehouse you want to include the onlyCoordinators setting for a request pool.
  4. Click Edit and navigate to Impala Coordinator under the Configurations tab.
  5. Select the fair-scheduler.xm under Configuration files.
  6. Add <onlyCoordinators>true</onlyCoordinators>. 
    <queue name="coords">
  <maxResources>10000 mb,0 vcores</maxResources>
  <onlyCoordinators>true</onlyCoordinators>
</queue>
  7. Click Apply Changes and restart Impala.