Package org.apache.hadoop.metrics2.lib

Class DefaultMetricsSystemHelper

java.lang.Object

org.apache.hadoop.metrics2.lib.DefaultMetricsSystemHelper

@Private
public class DefaultMetricsSystemHelper
extends Object

Field Summary

Fields

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

Constructor Summary

Constructors

Constructor	Description
DefaultMetricsSystemHelper()

Method Summary

Modifier and Type	Method	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 Details

LOG

private static final org.slf4j.Logger LOG

removeObjectMethod

private final Method removeObjectMethod

sourceNamesField

private final Field sourceNamesField

mapField

private final Field mapField

Constructor Details

DefaultMetricsSystemHelper

public DefaultMetricsSystemHelper()

Method Details

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.