com.hazelcast.internal.cluster.fd

Class PhiAccrualClusterFailureDetector

java.lang.Object

com.hazelcast.internal.cluster.fd.PhiAccrualClusterFailureDetector

All Implemented Interfaces:

ClusterFailureDetector

public class PhiAccrualClusterFailureDetector
extends Object
implements ClusterFailureDetector

Cluster failure detector based on 'The Phi Accrual Failure Detector' by Hayashibara et al. For more info see PhiAccrualFailureDetector

Field Summary

Fields

Modifier and Type	Field and Description
static HazelcastProperty	HEARTBEAT_PHI_FAILURE_DETECTOR_MIN_STD_DEV_MILLIS Minimum standard deviation to use for the normal distribution used when calculating phi.
static HazelcastProperty	HEARTBEAT_PHI_FAILURE_DETECTOR_SAMPLE_SIZE Number of samples to use for calculations.
static HazelcastProperty	HEARTBEAT_PHI_FAILURE_DETECTOR_THRESHOLD Threshold for suspicion level.

Constructor Summary

Constructors

Constructor and Description
PhiAccrualClusterFailureDetector(long maxNoHeartbeatMillis, long heartbeatIntervalMillis, double phiThreshold, int maxSampleSize, long minStdDeviationMillis)
PhiAccrualClusterFailureDetector(long maxNoHeartbeatMillis, long heartbeatIntervalMillis, HazelcastProperties props)

Method Summary

Modifier and Type	Method and Description
void	heartbeat(Member member, long timestamp) Notifies this failure detector about received heartbeat message from a member.
boolean	isAlive(Member member, long timestamp) Returns true if given member is considered as alive/available.
long	lastHeartbeat(Member member) Returns the last heartbeat timestamp for a member.
void	remove(Member member) Deregister member from tracking and cleanup resources related to this member.
void	reset() Clear all state kept by this failure detector
double	suspicionLevel(Member member, long timestamp) Returns suspicion level about a given member.

Methods inherited from class java.lang.Object

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

Field Detail

HEARTBEAT_PHI_FAILURE_DETECTOR_THRESHOLD

public static final HazelcastProperty HEARTBEAT_PHI_FAILURE_DETECTOR_THRESHOLD

Threshold for suspicion level. After calculated phi exceeds this threshold, a member is considered as dead.

• A low threshold allows to detect member crashes/failures faster but can generate more mistakes and cause wrong member suspicions.
• A high threshold generates fewer mistakes but is slower detect actual crashes/failures.

HEARTBEAT_PHI_FAILURE_DETECTOR_SAMPLE_SIZE

public static final HazelcastProperty HEARTBEAT_PHI_FAILURE_DETECTOR_SAMPLE_SIZE

Number of samples to use for calculations.

HEARTBEAT_PHI_FAILURE_DETECTOR_MIN_STD_DEV_MILLIS

public static final HazelcastProperty HEARTBEAT_PHI_FAILURE_DETECTOR_MIN_STD_DEV_MILLIS

Minimum standard deviation to use for the normal distribution used when calculating phi. Too low standard deviation might result in too much sensitivity.

Constructor Detail

PhiAccrualClusterFailureDetector

public PhiAccrualClusterFailureDetector(long maxNoHeartbeatMillis,
                                        long heartbeatIntervalMillis,
                                        HazelcastProperties props)

PhiAccrualClusterFailureDetector

public PhiAccrualClusterFailureDetector(long maxNoHeartbeatMillis,
                                        long heartbeatIntervalMillis,
                                        double phiThreshold,
                                        int maxSampleSize,
                                        long minStdDeviationMillis)

Method Detail

heartbeat

public void heartbeat(Member member,
                      long timestamp)

Description copied from interface: ClusterFailureDetector

Notifies this failure detector about received heartbeat message from a member.

Specified by:

heartbeat in interface ClusterFailureDetector

Parameters:

member - member which heartbeat message is received from

timestamp - timestamp of heartbeat message in milliseconds

isAlive

public boolean isAlive(Member member,
                       long timestamp)

Description copied from interface: ClusterFailureDetector

Returns true if given member is considered as alive/available.

Specified by:

isAlive in interface ClusterFailureDetector

Parameters:

member - member whose liveness is questioned

timestamp - timestamp in milliseconds

Returns:

true if member is alive

lastHeartbeat

public long lastHeartbeat(Member member)

Description copied from interface: ClusterFailureDetector

Returns the last heartbeat timestamp for a member.

Specified by:

lastHeartbeat in interface ClusterFailureDetector

Parameters:

member - member whose heartbeat timestamp is requested

Returns:

heartbeat timestamp in milliseconds

suspicionLevel

public double suspicionLevel(Member member,
                             long timestamp)

Description copied from interface: ClusterFailureDetector

Returns suspicion level about a given member. Returned value is mostly implementation dependent. 0 indicates no suspicion at all.

Specified by:

suspicionLevel in interface ClusterFailureDetector

Parameters:

member - member

timestamp - timestamp in milliseconds

Returns:

suspicion level

remove

public void remove(Member member)

Description copied from interface: ClusterFailureDetector

Deregister member from tracking and cleanup resources related to this member.

Specified by:

remove in interface ClusterFailureDetector

Parameters:

member - member to be removed

reset

public void reset()

Description copied from interface: ClusterFailureDetector

Clear all state kept by this failure detector

Specified by:

reset in interface ClusterFailureDetector