Package org.apache.pekko.routing

Class TailChoppingRoutingLogic

java.lang.Object

org.apache.pekko.routing.TailChoppingRoutingLogic

All Implemented Interfaces:

Serializable, NoSerializationVerificationNeeded, RoutingLogic, scala.Equals, scala.Product

public final class TailChoppingRoutingLogic
extends Object
implements RoutingLogic, scala.Product, Serializable

As each message is sent to the router, the routees are randomly ordered. The message is sent to the first routee. If no response is received before the interval has passed, the same message is sent to the next routee. This process repeats until either a response is received from some routee, the routees in the pool are exhausted, or the within duration has passed since the first send. If no routee sends a response in time, a pekko.actor.Status.Failure wrapping a pekko.pattern.AskTimeoutException is sent to the sender.

The goal of this routing algorithm is to decrease tail latencies ("chop off the tail latency") in situations where multiple routees can perform the same piece of work, and where a routee may occasionally respond more slowly than expected. In this case, sending the same work request (also known as a "backup request") to another actor results in decreased response time - because it's less probable that multiple actors are under heavy load simultaneously. This technique is explained in depth in Jeff Dean's presentation on Achieving Rapid Response Times in Large Online Services.

param: scheduler schedules sending messages to routees

param: within expecting at least one reply within this duration, otherwise it will reply with pekko.pattern.AskTimeoutException in a pekko.actor.Status.Failure

param: interval duration after which the message will be sent to the next routee

param: context execution context used by scheduler

See Also:

• Serialized Form

Constructor Summary

Constructors

Constructor	Description
TailChoppingRoutingLogic(Scheduler scheduler, scala.concurrent.duration.FiniteDuration within, scala.concurrent.duration.FiniteDuration interval, scala.concurrent.ExecutionContext context)

Method Summary

Modifier and Type	Method	Description
static TailChoppingRoutingLogic	apply(Scheduler scheduler, scala.concurrent.duration.FiniteDuration within, scala.concurrent.duration.FiniteDuration interval, scala.concurrent.ExecutionContext context)
boolean	canEqual(Object x$1)
scala.concurrent.ExecutionContext	context()
TailChoppingRoutingLogic	copy(Scheduler scheduler, scala.concurrent.duration.FiniteDuration within, scala.concurrent.duration.FiniteDuration interval, scala.concurrent.ExecutionContext context)
Scheduler	copy$default$1()
scala.concurrent.duration.FiniteDuration	copy$default$2()
scala.concurrent.duration.FiniteDuration	copy$default$3()
scala.concurrent.ExecutionContext	copy$default$4()
boolean	equals(Object x$1)
int	hashCode()
scala.concurrent.duration.FiniteDuration	interval()
int	productArity()
Object	productElement(int x$1)
String	productElementName(int x$1)
scala.collection.Iterator<Object>	productIterator()
String	productPrefix()
Scheduler	scheduler()
Routee	select(Object message, scala.collection.immutable.IndexedSeq<Routee> routees)	Pick the destination for a given message.
String	toString()
static scala.Option<scala.Tuple4<Scheduler,scala.concurrent.duration.FiniteDuration,scala.concurrent.duration.FiniteDuration,scala.concurrent.ExecutionContext>>	unapply(TailChoppingRoutingLogic x$0)
scala.concurrent.duration.FiniteDuration	within()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface scala.Product

productElementNames

Constructor Details

TailChoppingRoutingLogic

public TailChoppingRoutingLogic(Scheduler scheduler,
 scala.concurrent.duration.FiniteDuration within,
 scala.concurrent.duration.FiniteDuration interval,
 scala.concurrent.ExecutionContext context)

Method Details

apply

public static TailChoppingRoutingLogic apply(Scheduler scheduler,
 scala.concurrent.duration.FiniteDuration within,
 scala.concurrent.duration.FiniteDuration interval,
 scala.concurrent.ExecutionContext context)

unapply

public static scala.Option<scala.Tuple4<Scheduler,scala.concurrent.duration.FiniteDuration,scala.concurrent.duration.FiniteDuration,scala.concurrent.ExecutionContext>> unapply(TailChoppingRoutingLogic x$0)

scheduler

public Scheduler scheduler()

within

public scala.concurrent.duration.FiniteDuration within()

interval

public scala.concurrent.duration.FiniteDuration interval()

context

public scala.concurrent.ExecutionContext context()

select

public Routee select(Object message,
 scala.collection.immutable.IndexedSeq<Routee> routees)

Description copied from interface: RoutingLogic

Pick the destination for a given message. Normally it picks one of the passed routees, but in the end it is up to the implementation to return whatever pekko.routing.Routee to use for sending a specific message.

When implemented from Java it can be good to know that routees.apply(index) can be used to get an element from the IndexedSeq.

Specified by:

select in interface RoutingLogic

copy

public TailChoppingRoutingLogic copy(Scheduler scheduler,
 scala.concurrent.duration.FiniteDuration within,
 scala.concurrent.duration.FiniteDuration interval,
 scala.concurrent.ExecutionContext context)

copy$default$1

public Scheduler copy$default$1()

copy$default$2

public scala.concurrent.duration.FiniteDuration copy$default$2()

copy$default$3

public scala.concurrent.duration.FiniteDuration copy$default$3()

copy$default$4

public scala.concurrent.ExecutionContext copy$default$4()

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