org.apache.flink.streaming.runtime.tasks.mailbox

Class MailboxMetricsController

java.lang.Object

org.apache.flink.streaming.runtime.tasks.mailbox.MailboxMetricsController

@Internal
public class MailboxMetricsController
extends Object

Mailbox metrics controller class. The use of mailbox metrics, in particular scheduling latency measurements that require a TimerService, induce (cyclic) dependencies between MailboxProcessor and StreamTask. An instance of this class contains and gives control over these dependencies.

Field Summary

Fields

Modifier and Type	Field and Description
int	defaultLatencyMeasurementInterval Default timer interval in milliseconds for triggering mailbox latency measurement.

Constructor Summary

Constructors

Constructor and Description
MailboxMetricsController(Histogram latencyHistogram, Counter mailCounter) Creates instance of MailboxMetricsController with references to metrics provided as parameters.

Method Summary

Modifier and Type	Method and Description
Counter	getMailCounter() Gets Counter for number of mails processed.
boolean	isLatencyMeasurementSetup() Indicates if latency measurement has been setup.
boolean	isLatencyMeasurementStarted() Indicates if latency mesurement has been started.
void	measureMailboxLatency()
void	setLatencyMeasurementInterval(int measurementInterval)
void	setupLatencyMeasurement(TimerService timerService, MailboxExecutor mailboxExecutor) Sets up latency measurement with required TimerService and MailboxExecutor.
void	startLatencyMeasurement() Starts mailbox latency measurement.

Methods inherited from class java.lang.Object

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

Field Detail

defaultLatencyMeasurementInterval

public final int defaultLatencyMeasurementInterval

Default timer interval in milliseconds for triggering mailbox latency measurement.

See Also:

Constant Field Values

Constructor Detail

MailboxMetricsController

public MailboxMetricsController(Histogram latencyHistogram,
                                Counter mailCounter)

Creates instance of MailboxMetricsController with references to metrics provided as parameters.

Parameters:

latencyHistogram - Histogram of mailbox latency measurements.

mailCounter - Counter for number of mails processed.

Method Detail

setupLatencyMeasurement

public void setupLatencyMeasurement(TimerService timerService,
                                    MailboxExecutor mailboxExecutor)

Sets up latency measurement with required TimerService and MailboxExecutor.

Note: For each instance, latency measurement can be set up only once.

Parameters:

timerService - TimerService used for latency measurement.

mailboxExecutor - MailboxExecutor used for latency measurement.

startLatencyMeasurement

public void startLatencyMeasurement()

Starts mailbox latency measurement. This requires setup of latency measurement via setupLatencyMeasurement(TimerService, MailboxExecutor). Latency is measured through execution of a mail that is triggered by default in the interval defined by defaultLatencyMeasurementInterval.

Note: For each instance, latency measurement can be started only once.

isLatencyMeasurementStarted

public boolean isLatencyMeasurementStarted()

Indicates if latency mesurement has been started.

Returns:

True if latency measurement has been started.

isLatencyMeasurementSetup

public boolean isLatencyMeasurementSetup()

Indicates if latency measurement has been setup.

Returns:

True if latency measurement has been setup.

getMailCounter

public Counter getMailCounter()

Gets Counter for number of mails processed.

Returns:

Counter for number of mails processed.

setLatencyMeasurementInterval

@VisibleForTesting
public void setLatencyMeasurementInterval(int measurementInterval)

measureMailboxLatency

@VisibleForTesting
public void measureMailboxLatency()