Class PhiAccrualFailureDetector

Represents Phi Accrual implementation of the failure detector.

Inheritance

object

PhiAccrualFailureDetector

Implements

IFailureDetector

IResettable

ISupplier<double>

IFunctional<Func<double>>

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: DotNext.Diagnostics

Assembly: DotNext.Net.Cluster.dll

Syntax

public class PhiAccrualFailureDetector : IFailureDetector, IResettable, ISupplier<double>, IFunctional<Func<double>>

Constructors

PhiAccrualFailureDetector(TimeSpan)

Initializes a new failure detector.

Declaration

public PhiAccrualFailureDetector(TimeSpan estimatedFirstHeartbeat)

Parameters

Type	Name	Description
TimeSpan	estimatedFirstHeartbeat	The estimated interval to the first heartbeat.

Exceptions

Type	Condition
ArgumentOutOfRangeException	estimatedFirstHeartbeat is less than or equal to Zero.

Properties

AcceptableHeartbeatPause

Gets or sets duration corresponding to number of potentially lost/delayed heartbeats that will be accepted before considering it to be an anomaly.

Declaration

public TimeSpan AcceptableHeartbeatPause { get; init; }

Property Value

Type	Description
TimeSpan

Remarks

Too low standard deviation might result in too much sensitivity for sudden, but normal, deviations in heartbeat inter arrival times.

IsHealthy

Indicates that the resource associated with this detector is considered to be up and healthy.

Declaration

public bool IsHealthy { get; }

Property Value

Type	Description
bool

IsMonitoring

Indicates that this detector has received any heartbeats and started monitoring of the resource.

Declaration

public bool IsMonitoring { get; }

Property Value

Type	Description
bool

MaxSampleSize

Gets or sets a number of samples to use for calculation of mean and standard deviation of inter-arrival times.

Declaration

public int MaxSampleSize { get; init; }

Property Value

Type	Description
int

MinStdDeviation

Gets or sets minimum standard deviation to use for the normal distribution used when calculating phi.

Declaration

public TimeSpan MinStdDeviation { get; init; }

Property Value

Type	Description
TimeSpan

Remarks

Too low standard deviation might result in too much sensitivity for sudden, but normal, deviations in heartbeat inter-arrival times.

Threshold

Gets or sets Phi value threshold that is used to determine whether the underlying resource is no longer available.

Declaration

public double Threshold { get; init; }

Property Value

Type	Description
double

Remarks

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.

Exceptions

Type	Condition
ArgumentNullException	value is less than or equal to 0.

TreatUnknownValueAsUnhealthy

Gets or sets a value indicating that this detector interprets false value of IsMonitoring as unhealthy resource.

Declaration

public bool TreatUnknownValueAsUnhealthy { get; init; }

Property Value

Type	Description
bool

Remarks

By default, this property is false.

Value

Gets Phi value.

Declaration

public double Value { get; }

Property Value

Type	Description
double

Methods

GetValue(Timestamp)

Gets Phi value.

Declaration

public double GetValue(Timestamp ts)

Parameters

Type	Name	Description
Timestamp	ts	The timestamp of the heartbeat.

Returns

Type	Description
double	Phi value.

ReportHeartbeat()

Notifies that this detector received a heartbeat from the associated resource.

Declaration

public void ReportHeartbeat()

ReportHeartbeat(Timestamp)

Notifies that this detector received a heartbeat from the associated resource.

Declaration

public void ReportHeartbeat(Timestamp ts)

Parameters

Type	Name	Description
Timestamp	ts	The timestamp of the heartbeat.

Reset()

Resets this detector to its initial state.

Declaration

public void Reset()

Events

SuspiciousIntervalGrowth

An event occurred when this detector considers than the interval between two heartbeats is growing too fast.

Declaration

public event Action<TimeSpan> SuspiciousIntervalGrowth

Event Type

Type	Description
Action<TimeSpan>

Implements

IFailureDetector

IResettable

ISupplier<TResult>

IFunctional<TDelegate>

Extension Methods

BasicExtensions.As<T>(T)

BasicExtensions.GetUserData<T>(T)

BasicExtensions.IsBetween<T, TLowerBound, TUpperBound>(T, TLowerBound, TUpperBound)

BasicExtensions.IsOneOf<T>(T, ReadOnlySpan<T>)

ExpressionBuilder.Const<T>(T)

See Also

The Phi Accrual Failure Detector

Implementation in Scala