Manage metadata changes
Once you have connected your metastores, manage how metadata changes are detected by selecting a preferred operation mode when editing a metastore agent.
| Mode | Description |
|---|---|
| Listening (Default) | Listen for changes in real time if supported by your source environment. |
| Scanning | Periodically scan source metadata for changes. |
If your source environment is not configured to use Listeners, LiveData Migrator uses Scanning as the preferred operation mode.
If your source environment version isn't supported for Hive Migrator Listening mode, configure your source metastore agent to use Scanning as the preferred operation mode.
Configure your source metastore agent to use Scanning as the preferred operation mode if your source environment generates low or insufficient volumes of notifications from the events stream.
Listening mode requirements
Listening mode is supported for HDP 3.1.5 and CDP 7.1.x. See HVM listener event type limitations for more information. Users for any Hadoop version other than HDP 3.1.5 or CDP 7.1.x must select Scanning mode. For information on other Hadoop versions, contact support.
To enable Listening mode, you must have:
- A supported version of Hadoop. See HVM listener event type limitations for more information.
- The basic Prerequisites for Apache Hive.
- Listeners enabled on your cluster.
Enable listeners
Listeners are enabled by default in HDP 3.1.5 and CDP 7.1.x.
You can confirm that listeners are enabled for an agent using the hive agent check command.
If enabled, the response will show listenersEnabled: "true".
Next steps
See the following Knowledge base article for more information and actions you can take if outages or interruptions occur on metadata migrations where listeners are enabled.