Package org.apache.pekko.routing

Class DefaultResizer

java.lang.Object
org.apache.pekko.routing.DefaultResizer
All Implemented Interfaces:
Serializable, Resizer, scala.Equals, scala.Product
public class DefaultResizer extends Object implements Resizer, scala.Product, Serializable
See Also:

  • Constructor Details

    • DefaultResizer

      public DefaultResizer(int lowerBound, int upperBound, int pressureThreshold, double rampupRate, double backoffThreshold, double backoffRate, int messagesPerResize)

    • DefaultResizer

      public DefaultResizer(int lower, int upper)
      Java API constructor for default values except bounds.

  • Method Details

    • $lessinit$greater$default$1

      public static int $lessinit$greater$default$1()
      Implementation of Resizer that adjust the Pool based on specified thresholds.
      Parameters:
      lowerBound - The fewest number of routees the router should ever have.
      upperBound - The most number of routees the router should ever have. Must be greater than or equal to lowerBound.
      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.
      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.
      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.
      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.
      messagesPerResize - Number of messages between resize operation. Use 1 to resize before each message.

    • $lessinit$greater$default$2

      public static int $lessinit$greater$default$2()

    • $lessinit$greater$default$3

      public static int $lessinit$greater$default$3()

    • $lessinit$greater$default$4

      public static double $lessinit$greater$default$4()

    • $lessinit$greater$default$5

      public static double $lessinit$greater$default$5()

    • $lessinit$greater$default$6

      public static double $lessinit$greater$default$6()

    • $lessinit$greater$default$7

      public static int $lessinit$greater$default$7()

    • apply

      public static DefaultResizer apply(com.typesafe.config.Config resizerConfig)

    • apply$default$1

      public static int apply$default$1()
      Implementation of Resizer that adjust the Pool based on specified thresholds.
      Parameters:
      lowerBound - The fewest number of routees the router should ever have.
      upperBound - The most number of routees the router should ever have. Must be greater than or equal to lowerBound.
      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.
      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.
      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.
      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.
      messagesPerResize - Number of messages between resize operation. Use 1 to resize before each message.

    • apply$default$2

      public static int apply$default$2()

    • apply$default$3

      public static int apply$default$3()

    • apply$default$4

      public static double apply$default$4()

    • apply$default$5

      public static double apply$default$5()

    • apply$default$6

      public static double apply$default$6()

    • apply$default$7

      public static int apply$default$7()

    • fromConfig

      public static scala.Option<DefaultResizer> fromConfig(com.typesafe.config.Config resizerConfig)

    • apply

      public static DefaultResizer apply(int lowerBound, int upperBound, int pressureThreshold, double rampupRate, double backoffThreshold, double backoffRate, int messagesPerResize)
      Implementation of Resizer that adjust the Pool based on specified thresholds.
      Parameters:
      lowerBound - The fewest number of routees the router should ever have.
      upperBound - The most number of routees the router should ever have. Must be greater than or equal to lowerBound.
      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.
      • &gt; 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.
      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.
      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.
      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.
      messagesPerResize - Number of messages between resize operation. Use 1 to resize before each message.

    • unapply

      public static scala.Option<scala.Tuple7<Object,Object,Object,Object,Object,Object,Object>> unapply(DefaultResizer x$0)

    • productElementNames

      public static scala.collection.Iterator<String> productElementNames()

    • lowerBound

      public int lowerBound()

    • upperBound

      public int upperBound()

    • pressureThreshold

      public int pressureThreshold()

    • rampupRate

      public double rampupRate()

    • backoffThreshold

      public double backoffThreshold()

    • backoffRate

      public double backoffRate()

    • messagesPerResize

      public int messagesPerResize()

    • isTimeForResize

      public boolean isTimeForResize(long messageCounter)
      Description copied from interface: Resizer
      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.

      Specified by:
      isTimeForResize in interface Resizer

    • resize

      public int resize(scala.collection.immutable.IndexedSeq<Routee> currentRoutees)
      Description copied from interface: Resizer
      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.

      Specified by:
      resize in interface Resizer

    • capacity

      public int capacity(scala.collection.immutable.IndexedSeq<Routee> routees)
      Returns the overall desired change in resizer capacity. Positive value will add routees to the resizer. Negative value will remove routees from the resizer.
      Parameters:
      routees - The current actor in the resizer
      Returns:
      the number of routees by which the resizer should be adjusted (positive, negative or zero)

    • pressure

      public int pressure(scala.collection.immutable.IndexedSeq<Routee> routees)
      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.
      • &gt; 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.

      Parameters:
      routees - the current resizer of routees
      Returns:
      number of busy routees, between 0 and routees.size

    • filter

      public int filter(int pressure, int capacity)
      This method can be used to smooth the capacity delta by considering the current pressure and current capacity.

      Parameters:
      pressure - current number of busy routees
      capacity - current number of routees
      Returns:
      proposed change in the capacity

    • rampup

      public int rampup(int pressure, int capacity)
      Computes a proposed positive (or zero) capacity delta using the configured rampupRate.
      Parameters:
      pressure - the current number of busy routees
      capacity - the current number of total routees
      Returns:
      proposed increase in capacity

    • backoff

      public int backoff(int pressure, int capacity)
      Computes a proposed negative (or zero) capacity delta using the configured backoffThreshold and backoffRate
      Parameters:
      pressure - the current number of busy routees
      capacity - the current number of total routees
      Returns:
      proposed decrease in capacity (as a negative number)

    • copy

      public DefaultResizer copy(int lowerBound, int upperBound, int pressureThreshold, double rampupRate, double backoffThreshold, double backoffRate, int messagesPerResize)

    • copy$default$1

      public int copy$default$1()

    • copy$default$2

      public int copy$default$2()

    • copy$default$3

      public int copy$default$3()

    • copy$default$4

      public double copy$default$4()

    • copy$default$5

      public double copy$default$5()

    • copy$default$6

      public double copy$default$6()

    • copy$default$7

      public int copy$default$7()

    • productPrefix

      public String productPrefix()
      Specified by:
      productPrefix in interface scala.Product

    • productArity

      public int productArity()
      Specified by:
      productArity in interface scala.Product

    • productElement

      public Object productElement(int x$1)
      Specified by:
      productElement in interface scala.Product

    • productIterator

      public scala.collection.Iterator<Object> productIterator()
      Specified by:
      productIterator in interface scala.Product

    • canEqual

      public boolean canEqual(Object x$1)
      Specified by:
      canEqual in interface scala.Equals

    • productElementName

      public String productElementName(int x$1)
      Specified by:
      productElementName in interface scala.Product

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • equals

      public boolean equals(Object x$1)
      Specified by:
      equals in interface scala.Equals
      Overrides:
      equals in class Object