org.apache.hadoop.metrics2.lib

Class DefaultMetricsSystemHelper

java.lang.Object

org.apache.hadoop.metrics2.lib.DefaultMetricsSystemHelper

@InterfaceAudience.Private
public class DefaultMetricsSystemHelper
extends Object

Field Summary

Fields

Modifier and Type	Field and Description
private static org.slf4j.Logger	LOG
private Field	mapField
private Method	removeObjectMethod
private Field	sourceNamesField

Constructor Summary

Constructors

Constructor and Description
DefaultMetricsSystemHelper()

Method Summary

Modifier and Type	Method and Description
boolean	removeObjectName(String name)
void	removeSourceName(String name) Unfortunately Hadoop tries to be too-clever and permanently keeps track of all names registered so far as a Source, thus preventing further re-registration of the source with the same name.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LOG

private static final org.slf4j.Logger LOG

removeObjectMethod

private final Method removeObjectMethod

sourceNamesField

private final Field sourceNamesField

mapField

private final Field mapField

Constructor Detail

DefaultMetricsSystemHelper

public DefaultMetricsSystemHelper()

Method Detail

removeObjectName

public boolean removeObjectName(String name)

removeSourceName

public void removeSourceName(String name)

Unfortunately Hadoop tries to be too-clever and permanently keeps track of all names registered so far as a Source, thus preventing further re-registration of the source with the same name. In case of dynamic metrics tied to region-lifecycles, this becomes a problem because we would like to be able to re-register and remove with the same name. Otherwise, it is resource leak. This ugly code manually removes the name from the UniqueNames map. TODO: May not be needed for Hadoop versions after YARN-5190.