Example - Presto Plan Checker Router Scheduler Plugin

This package contains a custom scheduler plugin - Presto Plan Checker Router Scheduler Plugin.

Add the Custom Scheduler Plugin to the Presto Router

Place the plugin jar and all the dependent jars for the plugin in the plugin directory relative to the Presto install directory.

Create a configuration file for this plugin. The file must be named router-scheduler.properties and must be in the etc/router-config/ directory relative to the Presto install directory.

Set the scheduler name to CUSTOM_PLUGIN_SCHEDULER in etc/router-config.json.
scheduler: CUSTOM_PLUGIN_SCHEDULER

Main Classes:

• RouterSchedulerPlugin - Custom Scheduler Plugin class to be loaded by the Router plugin manager.
  This class implements the interface com.facebook.presto.spi.RouterPlugin.
• PlanCheckerRouterPluginSchedulerFactory - Factory for creating plan checker custom scheduler.
  This class implements the interface com.facebook.presto.spi.SchedulerFactory.
• PlanCheckerRouterPluginScheduler - Plan checker custom scheduler implementing the scheduling logic for clusters.
  This class implements the interface com.facebook.presto.spi.router.Scheduler.

Configuration:

The following configuration properties must be set in etc/router-config/router-scheduler.properties:

Property Name	Type	Description
router-scheduler.name	String	The name of the custom scheduler factory.
Example: router-scheduler.name=plan-checker
plan-check-clusters-uris	String	The URIs of the plan checker clusters.
router-java-url	String	The router URI dedicated to Java clusters.
router-native-url	String	The router URI dedicated to native clusters.
client-request-timeout	String	The maximum time the client will wait for a response before timing out.
Default : 2 minutes
enable-java-cluster-fallback	boolean	Enables fallback to the Java clusters when the plan checker clusters are unavailable or fail to process a request.
Default : false
enable-java-cluster-query-retry	boolean	Enables cross-cluster query retry.

When set to true, if a query fails on the native cluster, the system will automatically retry executing the query on the Java cluster. Default: false

Additional Details: When enable-java-cluster-query-retry is enabled, if the presto-plan-checker-router-plugin schedules a query on the native cluster (using the router-native-url) and the query execution fails, the query is automatically retried on a Java cluster (using the router-java-url).

The property router-native-url can point either to the native coordinator URL or to the router URL for the native cluster. Similarly, the property router-java-url can point either to the Java coordinator URL or to the router URL for the Java cluster. |