com.hazelcast.internal.diagnostics

Class StoreLatencyPlugin

java.lang.Object

com.hazelcast.internal.diagnostics.DiagnosticsPlugin

com.hazelcast.internal.diagnostics.StoreLatencyPlugin

public class StoreLatencyPlugin
extends DiagnosticsPlugin

A DiagnosticsPlugin that helps to detect if there are any performance issues with Stores/Loaders like e.g. MapStore.

This is done by instrumenting these Stores/Loaders with latency tracking probes, so that per Store/Loader all kinds of statistics like count, avg, mag, latency distribution etc is available.

One of the main purposes of this plugin is to make sure that e.g. a Database is the cause of slow performance. This plugin is useful to be combined with SlowOperationPlugin to get idea about where the threads are spending their time.

If this plugin is not enabled, there is no performance hit since the Stores/Loaders don't get decorated.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	StoreLatencyPlugin.LatencyProbe

Field Summary

Fields

Modifier and Type	Field and Description
static HazelcastProperty	PERIOD_SECONDS The period in seconds this plugin runs.
static HazelcastProperty	RESET_PERIOD_SECONDS The period in second the statistics should be reset.

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

logger

Constructor Summary

Constructors

Constructor and Description
StoreLatencyPlugin(ILogger logger, HazelcastProperties properties)
StoreLatencyPlugin(NodeEngineImpl nodeEngine)

Method Summary

Modifier and Type	Method and Description
long	count(String serviceName, String dataStructureName, String methodName)
long	getPeriodMillis() Returns the period of executing the monitor in millis.
StoreLatencyPlugin.LatencyProbe	newProbe(String serviceName, String dataStructureName, String methodName)
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.

If set to 0, the plugin is disabled.

RESET_PERIOD_SECONDS

public static final HazelcastProperty RESET_PERIOD_SECONDS

The period in second the statistics should be reset. Normally the statistics are not reset and if the system is running for an extended time, it isn't possible to see that happened in e.g. the last hour.

Currently there is no sliding window functionality to deal with this correctly. But for the time being this setting will periodically reset the statistics.

Constructor Detail

StoreLatencyPlugin

public StoreLatencyPlugin(NodeEngineImpl nodeEngine)

StoreLatencyPlugin

public StoreLatencyPlugin(ILogger logger,
                          HazelcastProperties properties)

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

count

public long count(String serviceName,
                  String dataStructureName,
                  String methodName)

newProbe

public StoreLatencyPlugin.LatencyProbe newProbe(String serviceName,
                                                String dataStructureName,
                                                String methodName)