com.hazelcast.internal.diagnostics

Class OperationThreadSamplerPlugin

java.lang.Object

com.hazelcast.internal.diagnostics.DiagnosticsPlugin

com.hazelcast.internal.diagnostics.OperationThreadSamplerPlugin

public class OperationThreadSamplerPlugin
extends DiagnosticsPlugin

The OperationThreadSamplerPlugin is a DiagnosticsPlugin that samples the operations threads and checks with operations/tasks are running. We have the slow operation detector; which is very useful for very slow operations. But it isn't useful for high volumes of not too slow operations. With the operation sampler we have a lot better understanding which operations are actually running.

Field Summary

Fields

Modifier and Type	Field and Description
static float	HUNDRED
static HazelcastProperty	INCLUDE_NAME If the name the data-structure the operation operates on should be included.
static HazelcastProperty	PERIOD_SECONDS The sample period in seconds.
static HazelcastProperty	SAMPLER_PERIOD_MILLIS The period in milliseconds between taking samples.

Fields inherited from class com.hazelcast.internal.diagnostics.DiagnosticsPlugin

logger

Constructor Summary

Constructors

Constructor and Description
OperationThreadSamplerPlugin(NodeEngineImpl nodeEngine)

Method Summary

Modifier and Type	Method and Description
long	getPeriodMillis() Returns the period of executing the monitor in millis.
void	onStart()
void	run(DiagnosticsLogWriter writer)

Methods inherited from class java.lang.Object

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

Field Detail

PERIOD_SECONDS

public static final HazelcastProperty PERIOD_SECONDS

The sample period in seconds. This is the frequency it will dump content to file. It isn't the frequency that the operations are being sampled.

If set to 0, the plugin is disabled.

SAMPLER_PERIOD_MILLIS

public static final HazelcastProperty SAMPLER_PERIOD_MILLIS

The period in milliseconds between taking samples. The lower the period, the higher the overhead, but also the higher the precision.

INCLUDE_NAME

public static final HazelcastProperty INCLUDE_NAME

If the name the data-structure the operation operates on should be included. WARNING: This feature should not be used in production because it can lead to quite a lot of litter and it can lead to uncontrolled memory growth because the samples of old data-structures will not be removed. Also each time the samples are taken, quite a lot of litter can be generated. So probably you do not want to have a too low SAMPLER_PERIOD_MILLIS because the lower it gets, the more litter is created.

HUNDRED

public static final float HUNDRED

See Also:

Constant Field Values

Constructor Detail

OperationThreadSamplerPlugin

public OperationThreadSamplerPlugin(NodeEngineImpl nodeEngine)

Method Detail

getPeriodMillis

public long getPeriodMillis()

Description copied from class: DiagnosticsPlugin

Returns the period of executing the monitor in millis.

If a monitor is disabled, 0 is returned.

If a monitor should run only once, a negative value is returned. This is useful for 'static' monitors like the SystemPropertiesPlugin that run at the beginning of a log file but their contents will not change.

Specified by:

getPeriodMillis in class DiagnosticsPlugin

Returns:

the period in millis.

onStart

public void onStart()

Specified by:

onStart in class DiagnosticsPlugin

run

public void run(DiagnosticsLogWriter writer)

Specified by:

run in class DiagnosticsPlugin