c

akka.routing

DefaultOptimalSizeExploringResizer

case class DefaultOptimalSizeExploringResizer(lowerBound: PoolSize = 1, upperBound: PoolSize = 30, chanceOfScalingDownWhenFull: Double = 0.2, actionInterval: Duration = 5.seconds, numOfAdjacentSizesToConsiderDuringOptimization: Int = 16, exploreStepSize: Double = 0.1, downsizeRatio: Double = 0.8, downsizeAfterUnderutilizedFor: Duration = 72.hours, explorationProbability: Double = 0.4, weightOfLatestMetric: Double = 0.5) extends OptimalSizeExploringResizer with Product with Serializable

This resizer resizes the pool to an optimal size that provides the most message throughput.

This resizer works best when you expect the pool size to performance function to be a convex function.

For example, when you have a CPU bound tasks, the optimal size is bound to the number of CPU cores. When your task is IO bound, the optimal size is bound to optimal number of concurrent connections to that IO service - e.g. a 4 node elastic search cluster may handle 4-8 concurrent requests at optimal speed.

It achieves this by keeping track of message throughput at each pool size and performing the following three resizing operations (one at a time) periodically:

* Downsize if it hasn't seen all routees ever fully utilized for a period of time. * Explore to a random nearby pool size to try and collect throughput metrics. * Optimize to a nearby pool size with a better (than any other nearby sizes) throughput metrics.

When the pool is fully-utilized (i.e. all routees are busy), it randomly choose between exploring and optimizing. When the pool has not been fully-utilized for a period of time, it will downsize the pool to the last seen max utilization multiplied by a configurable ratio.

By constantly exploring and optimizing, the resizer will eventually walk to the optimal size and remain nearby. When the optimal size changes it will start walking towards the new one.

It keeps a performance log so it's stateful as well as having a larger memory footprint than the default Resizer. The memory usage is O(n) where n is the number of sizes you allow, i.e. upperBound - lowerBound.

For documentation about the parameters, see the reference.conf - akka.actor.deployment.default.optimal-size-exploring-resizer

Annotations
@SerialVersionUID()
Source
OptimalSizeExploringResizer.scala
Linear Supertypes
Serializable, Product, Equals, OptimalSizeExploringResizer, Resizer, AnyRef, Any
Type Hierarchy
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Inherited
  1. DefaultOptimalSizeExploringResizer
  2. Serializable
  3. Product
  4. Equals
  5. OptimalSizeExploringResizer
  6. Resizer
  7. AnyRef
  8. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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Visibility
  1. Public
  2. Protected

Instance Constructors

  1. new DefaultOptimalSizeExploringResizer(lowerBound: PoolSize = 1, upperBound: PoolSize = 30, chanceOfScalingDownWhenFull: Double = 0.2, actionInterval: Duration = 5.seconds, numOfAdjacentSizesToConsiderDuringOptimization: Int = 16, exploreStepSize: Double = 0.1, downsizeRatio: Double = 0.8, downsizeAfterUnderutilizedFor: Duration = 72.hours, explorationProbability: Double = 0.4, weightOfLatestMetric: Double = 0.5)

Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##: Int
    Definition Classes
    AnyRef → Any
  3. def +(other: String): String
    Implicit
    This member is added by an implicit conversion from DefaultOptimalSizeExploringResizer toany2stringadd[DefaultOptimalSizeExploringResizer] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (DefaultOptimalSizeExploringResizer, B)
    Implicit
    This member is added by an implicit conversion from DefaultOptimalSizeExploringResizer toArrowAssoc[DefaultOptimalSizeExploringResizer] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  5. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  6. val actionInterval: Duration
  7. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  8. val chanceOfScalingDownWhenFull: Double
  9. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.CloneNotSupportedException]) @HotSpotIntrinsicCandidate() @native()
  10. val downsizeAfterUnderutilizedFor: Duration
  11. val downsizeRatio: Double
  12. def ensuring(cond: (DefaultOptimalSizeExploringResizer) => Boolean, msg: => Any): DefaultOptimalSizeExploringResizer
    Implicit
    This member is added by an implicit conversion from DefaultOptimalSizeExploringResizer toEnsuring[DefaultOptimalSizeExploringResizer] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  13. def ensuring(cond: (DefaultOptimalSizeExploringResizer) => Boolean): DefaultOptimalSizeExploringResizer
    Implicit
    This member is added by an implicit conversion from DefaultOptimalSizeExploringResizer toEnsuring[DefaultOptimalSizeExploringResizer] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  14. def ensuring(cond: Boolean, msg: => Any): DefaultOptimalSizeExploringResizer
    Implicit
    This member is added by an implicit conversion from DefaultOptimalSizeExploringResizer toEnsuring[DefaultOptimalSizeExploringResizer] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  15. def ensuring(cond: Boolean): DefaultOptimalSizeExploringResizer
    Implicit
    This member is added by an implicit conversion from DefaultOptimalSizeExploringResizer toEnsuring[DefaultOptimalSizeExploringResizer] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  16. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  17. val explorationProbability: Double
  18. val exploreStepSize: Double
  19. final def getClass(): Class[_ <: AnyRef]
    Definition Classes
    AnyRef → Any
    Annotations
    @HotSpotIntrinsicCandidate() @native()
  20. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  21. def isTimeForResize(messageCounter: Long): Boolean

    Is it time for resizing.

    Is it time for resizing. Typically implemented with modulo of nth message, but could be based on elapsed time or something else. The messageCounter starts with 0 for the initial resize and continues with 1 for the first message. Make sure to perform initial resize before first message (messageCounter == 0), because there is no guarantee that resize will be done when concurrent messages are in play.

    CAUTION: this method is invoked from the thread which tries to send a message to the pool, i.e. the ActorRef.!() method, hence it may be called concurrently.

    Definition Classes
    DefaultOptimalSizeExploringResizer → Resizer
  22. val lowerBound: PoolSize
  23. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  24. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @HotSpotIntrinsicCandidate() @native()
  25. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @HotSpotIntrinsicCandidate() @native()
  26. val numOfAdjacentSizesToConsiderDuringOptimization: Int
  27. def productElementNames: Iterator[String]
    Definition Classes
    Product
  28. def reportMessageCount(currentRoutees: IndexedSeq[Routee], messageCounter: Long): Unit

    Report the messageCount as well as current routees so that the it can collect metrics.

    Report the messageCount as well as current routees so that the it can collect metrics. Caution: this method is not thread safe.

    Definition Classes
    DefaultOptimalSizeExploringResizer → OptimalSizeExploringResizer
  29. def resize(currentRoutees: IndexedSeq[Routee]): Int

    Decide if the capacity of the router need to be changed.

    Decide if the capacity of the router need to be changed. Will be invoked when isTimeForResize returns true and no other resize is in progress.

    Return the number of routees to add or remove. Negative value will remove that number of routees. Positive value will add that number of routees. 0 will not change the routees.

    This method is invoked only in the context of the Router actor.

    Definition Classes
    DefaultOptimalSizeExploringResizer → Resizer
  30. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
    AnyRef
  31. val upperBound: PoolSize
  32. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  33. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()
  34. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  35. val weightOfLatestMetric: Double

Deprecated Value Members

  1. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.Throwable]) @Deprecated
    Deprecated

    (Since version 9)

  2. def formatted(fmtstr: String): String
    Implicit
    This member is added by an implicit conversion from DefaultOptimalSizeExploringResizer toStringFormat[DefaultOptimalSizeExploringResizer] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @deprecated @inline()
    Deprecated

    (Since version 2.12.16) Use formatString.format(value) instead of value.formatted(formatString), or use the f"" string interpolator. In Java 15 and later, formatted resolves to the new method in String which has reversed parameters.

  3. def →[B](y: B): (DefaultOptimalSizeExploringResizer, B)
    Implicit
    This member is added by an implicit conversion from DefaultOptimalSizeExploringResizer toArrowAssoc[DefaultOptimalSizeExploringResizer] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @deprecated
    Deprecated

    (Since version 2.13.0) Use -> instead. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code.

Inherited from Serializable

Inherited from Product

Inherited from Equals

Inherited from OptimalSizeExploringResizer

Inherited from Resizer

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd fromDefaultOptimalSizeExploringResizer to any2stringadd[DefaultOptimalSizeExploringResizer]

Inherited by implicit conversion StringFormat fromDefaultOptimalSizeExploringResizer to StringFormat[DefaultOptimalSizeExploringResizer]

Inherited by implicit conversion Ensuring fromDefaultOptimalSizeExploringResizer to Ensuring[DefaultOptimalSizeExploringResizer]

Inherited by implicit conversion ArrowAssoc fromDefaultOptimalSizeExploringResizer to ArrowAssoc[DefaultOptimalSizeExploringResizer]

Ungrouped