com.hazelcast.config

Class ProbabilisticQuorumConfigBuilder

java.lang.Object

com.hazelcast.config.QuorumConfigBuilder

com.hazelcast.config.ProbabilisticQuorumConfigBuilder

public class ProbabilisticQuorumConfigBuilder
extends QuorumConfigBuilder

Builder for a QuorumConfig configured with ProbabilisticQuorumFunction that considers members present in the context of a quorum using a probabilistic, adaptive quorum function.

Field Summary

Fields

Modifier and Type	Field and Description
static long	DEFAULT_HEARTBEAT_INTERVAL_MILLIS Default value of heartbeat interval (in milliseconds).
static long	DEFAULT_HEARTBEAT_PAUSE_MILLIS Default duration in milliseconds corresponding to number of potentially lost/delayed heartbeats that will be accepted before considering it to be an anomaly.
static long	DEFAULT_MIN_STD_DEVIATION Default minimum standard deviation (in milliseconds) to use for the normal distribution used when calculating phi.
static double	DEFAULT_PHI_THRESHOLD Default threshold for suspicion (φ) level.
static int	DEFAULT_SAMPLE_SIZE Default number of samples to use for calculation of mean and standard deviation of inter-arrival times.

Fields inherited from class com.hazelcast.config.QuorumConfigBuilder

enabled, size

Method Summary

Modifier and Type	Method and Description
QuorumConfig	build()
ProbabilisticQuorumConfigBuilder	withAcceptableHeartbeatPauseMillis(long acceptableHeartbeatPauseMillis) Duration in milliseconds corresponding to number of potentially lost/delayed heartbeats that will be accepted before considering it to be an anomaly.
ProbabilisticQuorumConfigBuilder	withHeartbeatIntervalMillis(long heartbeatIntervalMillis) Bootstrap the stats with heartbeats that corresponds to this duration in milliseconds, with a rather high standard deviation (since environment is unknown in the beginning).
ProbabilisticQuorumConfigBuilder	withMaxSampleSize(int maxSampleSize) Number of samples to use for calculation of mean and standard deviation of inter-arrival times.
ProbabilisticQuorumConfigBuilder	withMinStdDeviationMillis(long minStdDeviationMillis) Minimum standard deviation (in milliseconds) to use for the normal distribution used when calculating phi.
ProbabilisticQuorumConfigBuilder	withSuspicionThreshold(double suspicionThreshold) Threshold for suspicion (φ) level.

Methods inherited from class com.hazelcast.config.QuorumConfigBuilder

enabled, withQuorumSize

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_PHI_THRESHOLD

public static final double DEFAULT_PHI_THRESHOLD

Default threshold for suspicion (φ) level.

DEFAULT_SAMPLE_SIZE

public static final int DEFAULT_SAMPLE_SIZE

Default number of samples to use for calculation of mean and standard deviation of inter-arrival times.

DEFAULT_MIN_STD_DEVIATION

public static final long DEFAULT_MIN_STD_DEVIATION

Default minimum standard deviation (in milliseconds) to use for the normal distribution used when calculating phi.

DEFAULT_HEARTBEAT_PAUSE_MILLIS

public static final long DEFAULT_HEARTBEAT_PAUSE_MILLIS

Default duration in milliseconds corresponding to number of potentially lost/delayed heartbeats that will be accepted before considering it to be an anomaly.

DEFAULT_HEARTBEAT_INTERVAL_MILLIS

public static final long DEFAULT_HEARTBEAT_INTERVAL_MILLIS

Default value of heartbeat interval (in milliseconds).

Method Detail

withSuspicionThreshold

public ProbabilisticQuorumConfigBuilder withSuspicionThreshold(double suspicionThreshold)

Threshold for suspicion (φ) level. A low threshold is prone to generate many wrong suspicions but ensures a quick detection in the event of a real crash. Conversely, a high threshold generates fewer mistakes but needs more time to detect actual crashes.

withMaxSampleSize

public ProbabilisticQuorumConfigBuilder withMaxSampleSize(int maxSampleSize)

Number of samples to use for calculation of mean and standard deviation of inter-arrival times.

withMinStdDeviationMillis

public ProbabilisticQuorumConfigBuilder withMinStdDeviationMillis(long minStdDeviationMillis)

Minimum standard deviation (in milliseconds) to use for the normal distribution used when calculating phi. Too low standard deviation might result in too much sensitivity for sudden, but normal, deviations in heartbeat inter arrival times.

withAcceptableHeartbeatPauseMillis

public ProbabilisticQuorumConfigBuilder withAcceptableHeartbeatPauseMillis(long acceptableHeartbeatPauseMillis)

Duration in milliseconds corresponding to number of potentially lost/delayed heartbeats that will be accepted before considering it to be an anomaly. This margin is important to be able to survive sudden, occasional, pauses in heartbeat arrivals, due to for example garbage collection or network drops.

withHeartbeatIntervalMillis

public ProbabilisticQuorumConfigBuilder withHeartbeatIntervalMillis(long heartbeatIntervalMillis)

Bootstrap the stats with heartbeats that corresponds to this duration in milliseconds, with a rather high standard deviation (since environment is unknown in the beginning).

build

public QuorumConfig build()

Specified by:

build in class QuorumConfigBuilder