Class DefaultResizer

Implementation of Resizer that adjust the Pool based on specified thresholds.

Inheritance

object

Resizer

DefaultResizer

Implements

IEquatable<DefaultResizer>

Inherited Members

object.Equals(object, object)

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: Akka.Routing

Assembly: Akka.dll

Syntax

public class DefaultResizer : Resizer, IEquatable<DefaultResizer>

Constructors

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DefaultResizer(int, int, int, double, double, double, int)

Initializes a new instance of the DefaultResizer class.

Declaration

public DefaultResizer(int lower, int upper, int pressureThreshold = 1, double rampupRate = 0.2, double backoffThreshold = 0.3, double backoffRate = 0.1, int messagesPerResize = 10)

Parameters

Type	Name	Description
int	lower	TBD
int	upper	TBD
int	pressureThreshold	TBD
double	rampupRate	TBD
double	backoffThreshold	TBD
double	backoffRate	TBD
int	messagesPerResize	TBD

Exceptions

Type Condition

Type	Condition
ArgumentException	This exception can be thrown for a number of reasons. These include: The given `lower` bound was negative. The given `upper` bound was negative. The given `upper` bound was below the `lower`bound. The given `rampupRate` was negative. The given `backoffThreshold` was greater than one. The given `backoffRate` was negative. The given `messagesPerResize` was less than one.

ArgumentException

This exception can be thrown for a number of reasons. These include:

The given lower bound was negative.
The given upper bound was negative.
The given upper bound was below the lowerbound.
The given rampupRate was negative.
The given backoffThreshold was greater than one.
The given backoffRate was negative.
The given messagesPerResize was less than one.

Properties

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BackoffRate

Fraction of routees to be removed when the resizer reaches the backoffThreshold. For example, 0.1 would decrease 10% (rounded up), i.e. if current capacity is 9 it will request an decrease of 1 routee.

Declaration

public double BackoffRate { get; }

Property Value

Type	Description
double

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BackoffThreshold

Minimum fraction of busy routees before backing off. For example, if this is 0.3, then we'll remove some routees only when less than 30% of routees are busy, i.e. if current capacity is 10 and 3 are busy then the capacity is unchanged, but if 2 or less are busy the capacity is decreased.

Use 0.0 or negative to avoid removal of routees.

Declaration

public double BackoffThreshold { get; }

Property Value

Type	Description
double

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LowerBound

The fewest number of routees the router should ever have.

Declaration

public int LowerBound { get; set; }

Property Value

Type	Description
int

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MessagesPerResize

Number of messages between resize operation. Use 1 to resize before each message.

Declaration

public int MessagesPerResize { get; }

Property Value

Type	Description
int

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PressureThreshold

Threshold to evaluate if routee is considered to be busy (under pressure). Implementation depends on this value (default is 1).

0: number of routees currently processing a message.
1: number of routees currently processing a message has some messages in mailbox.
> 1: number of routees with at least the configured `pressureThreshold` messages in their mailbox. Note that estimating mailbox size of default UnboundedMailbox is O(N) operation.

Declaration

public int PressureThreshold { get; }

Property Value

Type	Description
int

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RampupRate

Percentage to increase capacity whenever all routees are busy. For example, 0.2 would increase 20% (rounded up), i.e. if current capacity is 6 it will request an increase of 2 more routees.

Declaration

public double RampupRate { get; }

Property Value

Type	Description
double

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UpperBound

The most number of routees the router should ever have. Must be greater than or equal to lowerBound.

Declaration

public int UpperBound { get; set; }

Property Value

Type	Description
int

Methods

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Backoff(int, int)

Computes a proposed negative (or zero) capacity delta using the configured backoffThreshold and backoffRate

Declaration

public int Backoff(int pressure, int capacity)

Parameters

Type	Name	Description
int	pressure	pressure current number of busy routees
int	capacity	capacity current number of routees

Returns

Type	Description
int	proposed decrease in capacity (as a negative number)

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Capacity(IEnumerable<Routee>)

Returns the overall desired change in resizer capacity. Positive value will add routees to the resizer. Negative value will remove routees from the resizer

Declaration

public int Capacity(IEnumerable<Routee> currentRoutees)

Parameters

Type	Name	Description
IEnumerable<Routee>	currentRoutees	The current actor in the resizer

Returns

Type	Description
int	the number of routees by which the resizer should be adjusted (positive, negative or zero)

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Equals(DefaultResizer)

Declaration

public bool Equals(DefaultResizer other)

Parameters

Type	Name	Description
DefaultResizer	other

Returns

Type	Description
bool

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Equals(object)

Declaration

public override bool Equals(object obj)

Parameters

Type	Name	Description
object	obj

Returns

Type	Description
bool

Overrides

object.Equals(object)

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Filter(int, int)

This method can be used to smooth the capacity delta by considering the current pressure and current capacity.

Declaration

public int Filter(int pressure, int capacity)

Parameters

Type	Name	Description
int	pressure	pressure current number of busy routees
int	capacity	capacity current number of routees

Returns

Type	Description
int	proposed change in the capacity

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FromConfig(Config)

TBD

Declaration

public static DefaultResizer FromConfig(Config resizerConfig)

Parameters

Type	Name	Description
Config	resizerConfig	TBD

Returns

Type	Description
DefaultResizer	TBD

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GetHashCode()

Declaration

public override int GetHashCode()

Returns

Type	Description
int

Overrides

object.GetHashCode()

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IsTimeForResize(long)

TBD

Declaration

public override bool IsTimeForResize(long messageCounter)

Parameters

Type	Name	Description
long	messageCounter	TBD

Returns

Type	Description
bool	TBD

Overrides

Resizer.IsTimeForResize(long)

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Pressure(IEnumerable<Routee>)

Number of routees considered busy, or above 'pressure level'.

Implementation depends on the value of pressureThreshold (default is 1).

0: number of routees currently processing a message.
1: number of routees currently processing a message has some messages in mailbox.
> 1: number of routees with at least the configured `pressureThreshold` messages in their mailbox. Note that estimating mailbox size of default UnboundedMailbox is O(N) operation.

Declaration

public int Pressure(IEnumerable<Routee> currentRoutees)

Parameters

Type	Name	Description
IEnumerable<Routee>	currentRoutees	An enumeration of the current routees

Returns

Type	Description
int	The number of routees considered to be above pressure level.

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Rampup(int, int)

Computes a proposed positive (or zero) capacity delta using the configured rampupRate.

Declaration

public int Rampup(int pressure, int capacity)

Parameters

Type	Name	Description
int	pressure	the current number of busy routees
int	capacity	the current number of total routees

Returns

Type	Description
int	proposed increase in capacity

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Resize(IEnumerable<Routee>)

TBD

Declaration

public override int Resize(IEnumerable<Routee> currentRoutees)

Parameters

Type	Name	Description
IEnumerable<Routee>	currentRoutees	TBD

Returns

Type	Description
int	TBD