com.hazelcast.internal.diagnostics

Class OperationHeartbeatPlugin

java.lang.Object

com.hazelcast.internal.diagnostics.DiagnosticsPlugin

com.hazelcast.internal.diagnostics.OperationHeartbeatPlugin

public class OperationHeartbeatPlugin
extends DiagnosticsPlugin

A diagnostics plugin that checks how the network is behaving by checking deviations in Operation-heartbeats to assist with network related problems like split-brain.

It does this by checking the deviation in the interval between operation-heartbeat packets. Operation-heartbeat packets are sent at a fixed interval (operation-call-timeout/4) and are not processed by operation-threads, but by their own system. If there is a big deviation, then it could indicate networking problems. But it could also indicate other problems like JVM issues.

Field Summary

Fields

Modifier and Type	Field and Description
static HazelcastProperty	MAX_DEVIATION_PERCENTAGE The maximum allowed deviation.
static HazelcastProperty	PERIOD_SECONDS The period in seconds this plugin runs.

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

logger

Constructor Summary

Constructors

Constructor and Description
OperationHeartbeatPlugin(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 period in seconds this plugin runs.

This plugin is very cheap to run and is enabled by default.

It will also not print output every time it is executed, only when one or more members have a too high operation-heartbeat deviation, the plugin will render output.

If set to 0, the plugin is disabled.

MAX_DEVIATION_PERCENTAGE

public static final HazelcastProperty MAX_DEVIATION_PERCENTAGE

The maximum allowed deviation. E.g. with a default 60 call timeout and operation-heartbeat interval being 15 seconds, the maximum deviation with a deviation-percentage of 33, is 5 seconds. So if a packet is arrived after 19 seconds; no problem; but if it arrives after 21 seconds, then the plugin will render.

Constructor Detail

OperationHeartbeatPlugin

public OperationHeartbeatPlugin(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