org.apache.hadoop.hbase.util

Class JvmPauseMonitor

java.lang.Object

org.apache.hadoop.hbase.util.JvmPauseMonitor

@InterfaceAudience.Private
public class JvmPauseMonitor
extends Object

Class which sets up a simple thread which runs in a loop sleeping for a short interval of time. If the sleep takes significantly longer than its target time, it implies that the JVM or host machine has paused processing, which may cause other problems. If such a pause is detected, the thread logs a message. The original JvmPauseMonitor is: ${hadoop-common-project}/hadoop-common/src/main/java/org/apache/hadoop/util/ JvmPauseMonitor.java r1503806 | cmccabe | 2013-07-17 01:48:24 +0800 (Wed, 17 Jul 2013) | 1 line HADOOP-9618. thread which detects GC pauses(Todd Lipcon)

Field Summary

Fields

Modifier and Type	Field and Description
static String	INFO_THRESHOLD_KEY
static String	WARN_THRESHOLD_KEY

Constructor Summary

Constructors

Constructor and Description
JvmPauseMonitor(org.apache.hadoop.conf.Configuration conf)
JvmPauseMonitor(org.apache.hadoop.conf.Configuration conf, JvmPauseMonitorSource metricsSource)

Method Summary

Modifier and Type	Method and Description
JvmPauseMonitorSource	getMetricsSource()
static void	main(String[] args) Simple 'main' to facilitate manual testing of the pause monitor.
void	setMetricsSource(JvmPauseMonitorSource metricsSource)
void	start()
void	stop()
void	updateMetrics(long sleepTime, boolean gcDetected)

Methods inherited from class java.lang.Object

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

Field Detail

WARN_THRESHOLD_KEY

public static final String WARN_THRESHOLD_KEY

See Also:

Constant Field Values

INFO_THRESHOLD_KEY

public static final String INFO_THRESHOLD_KEY

See Also:

Constant Field Values

Constructor Detail

JvmPauseMonitor

public JvmPauseMonitor(org.apache.hadoop.conf.Configuration conf)

JvmPauseMonitor

public JvmPauseMonitor(org.apache.hadoop.conf.Configuration conf,
                       JvmPauseMonitorSource metricsSource)

Method Detail

start

public void start()

stop

public void stop()

updateMetrics

public void updateMetrics(long sleepTime,
                          boolean gcDetected)

getMetricsSource

public JvmPauseMonitorSource getMetricsSource()

setMetricsSource

public void setMetricsSource(JvmPauseMonitorSource metricsSource)

main

public static void main(String[] args)
                 throws Exception

Simple 'main' to facilitate manual testing of the pause monitor. This main function just leaks memory into a list. Running this class with a 1GB heap will very quickly go into "GC hell" and result in log messages about the GC pauses.

Throws:

Exception