Known issues in Impala Virtual Warehouses

Known Issues identified in 1.5.1

DWX-15182: Performance degradation due to a configurations copied from the base cluster

If you have enabled the Copy configurations from base cluster to CDW option from Advanced Configurations, then all base cluster configurations, including fe_service_threads are copied to CDW. The fe_service_threads configuration impacts client concurrent connections. You may see degraded performance if the value of this configuration is set to anything less than 96 on the base cluster.

Ensure that the value of this property is at least 96.

DWX-15869: Virtual Warehouse edit page does not load

If the Trusted Kerberos Realms configuration on the base cluster's Core Settings service is not empty or if the Additional Rules to Map Kerberos Principals to Short Names field (auth_to_local_rule property) contains the following characters: \, ", \t, \n, \b, and \f, then the CDW Database Catalog and Virtual Warehouse edit page does not load. The logs of the dwx-server pod in the control plane namespace contain the following error message: Not able to render config, err:invalid character 'Q' in string escape code.

If the Trusted Kerberos Realms property is configured, then perform the folowing:

1. Log in to Cloudera Manager as an Administrator.
2. Go to Clusters > Core Settings service > Actions, click Download Client Configuration. Save the file on your computer and decompress it.
3. Open the core-site.xml file and copy the value of the hadoop.security.auth_to_local configuration property.
4. Paste the value of the hadoop.security.auth_to_local configuration property in a text editor and remove all \Q and \E regular expression constructs. Copy the modified text.
5. Go to Cloudera Manager > Clusters > Core Settings service > Configuration and paste the modified text in the Additional Rules to Map Kerberos Principals to Short Names field.
6. Remove the Trusted Kerberos Realms configuration from Core Settings service > Configuration tab.
7. Click Save Changes.
8. Restart the affected services in Cloudera Manager to apply stale configurations.
9. Go to the Data Warehouse service and refresh your Database Catalogs and Virtual Warehouses. In case this does not work, deactivate and reactivate your environment in CDW.

If the Additional Rules to Map Kerberos Principals to Short Names field (extra_auth_to_local_rules property) in Core Settings service contains the following characters: \, ", \t, \n, \b, and \f, then remove these characters regular expression. Save changes and restart the affected services in Cloudera Manager, and then refresh the Database Catalog and Virtual Warehouses.

DWX-15537: Kerberos authentication throwing "user not authorized error" after updating a usergroup in an Impala Virtual Warehouse

You may see an “User is not authorized” error when opening a session with Kerberos authentication to an Impala Virtual Warehouse where the access is restricted to user groups listed in the Virtual Warehouse settings. This problem may occur only when trying to connect with the same user as the delegation user specified during CDP Private Cloud Data Services environment activation.

To successfully connect to an Impala Virtual Warehouse from an impala-shell client using Kerberos, define the Impala delegation user (impala.doas.user) in the JDBC URL or in the impala-shell command. Ensure that the username is exactly the same as the one that you used to activate the Private Cloud Data Services environment and for which a Kerberos ticket was obtained at the time of the error.

DWX-15032: Impala Virtual Warehouse transitions to a running state way before the update finishes

When an Impala Virtual Warehouse is in an Updating or Upgrading state after an edit or upgrade operation the Virtual Warehouse transitions to a Running or Stopped state before the update process finishes. When the warehouse is in a Running or Stopped state after updating it, the changes made to the Virtual Warehouse, might not take effect until later.

To confirm whether the update has completed, check if the following log message is displayed in the dwx-server logs: "Virtual Warehouse update completed".

DWX-14292: Impala executors and coordinator pods get stuck in pending state

If you have enabled low resource mode while activating an environment in CDW and also enabled the option to customize pod sizes for Impala from the Advanced Settings page, then you may notice that the executors and coordinator pods do not request the set amount of memory and CPU. This happens because the low resource mode overrides the default pod configuration.

Low resource mode and custom pod configurations for Impala cannot be used at the same time. To resolve this issue, do not select the Low resource mode option while activating an environment. Instead, create custom pod configurations with lower resources for Impala. You can continue to use lesser resources as defined in the custom pod configuration for Hive.

VIZ-2046: Trusted impersonation does not work in CDW

When you try to create a connection to the Impala Virtual Warehouse from Cloudera Data Visualization (CDV), CDV is unable to use Trusted Impersonation as a mode of authentication. Therefore, you need to enter both the username and password for authentication.

None.