class ConsistentHashingShardAllocationStrategy extends ActorSystemDependentAllocationStrategy with ClusterShardAllocationMixin

akka.cluster.sharding.ShardCoordinator.ShardAllocationStrategy that is using consistent hashing. This can be useful when shards with the same shard id for different entity types should be best effort colocated to the same nodes.

When adding or removing nodes it will rebalance according to the new consistent hashing, but that means that only a few shards will be rebalanced and others remain on the same location.

A good explanation of Consistent Hashing: https://tom-e-white.com/2007/11/consistent-hashing.html

Create a new instance of this for each entity types, i.e. a ConsistentHashingShardAllocationStrategy instance must not be shared between different entity types.

Not intended for public inheritance/implementation

Annotations
@DoNotInherit()
Source
ConsistentHashingShardAllocationStrategy.scala
Linear Supertypes
ClusterShardAllocationMixin, ActorSystemDependentAllocationStrategy, ShardAllocationStrategy, NoSerializationVerificationNeeded, AnyRef, Any
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Inherited
  1. ConsistentHashingShardAllocationStrategy
  2. ClusterShardAllocationMixin
  3. ActorSystemDependentAllocationStrategy
  4. ShardAllocationStrategy
  5. NoSerializationVerificationNeeded
  6. AnyRef
  7. 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 ConsistentHashingShardAllocationStrategy(rebalanceLimit: Int)

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 ConsistentHashingShardAllocationStrategy toany2stringadd[ConsistentHashingShardAllocationStrategy] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (ConsistentHashingShardAllocationStrategy, B)
    Implicit
    This member is added by an implicit conversion from ConsistentHashingShardAllocationStrategy toArrowAssoc[ConsistentHashingShardAllocationStrategy] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  5. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  6. def allocateShard(requester: ActorRef, shardId: ShardId, currentShardAllocations: Map[ActorRef, IndexedSeq[ShardId]]): Future[ActorRef]

    Invoked when the location of a new shard is to be decided.

    Invoked when the location of a new shard is to be decided.

    requester

    actor reference to the ShardRegion that requested the location of the shard, can be returned if preference should be given to the node where the shard was first accessed

    shardId

    the id of the shard to allocate

    currentShardAllocations

    all actor refs to ShardRegion and their current allocated shards, in the order they were allocated

    returns

    a Future of the actor ref of the ShardRegion that is to be responsible for the shard, must be one of the references included in the currentShardAllocations parameter

    Definition Classes
    ConsistentHashingShardAllocationStrategyShardAllocationStrategy
    Annotations
    @nowarn()
  7. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  8. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.CloneNotSupportedException]) @native() @HotSpotIntrinsicCandidate()
  9. def clusterState: CurrentClusterState
    Attributes
    protected
    Definition Classes
    ConsistentHashingShardAllocationStrategy → ClusterShardAllocationMixin
  10. def ensuring(cond: (ConsistentHashingShardAllocationStrategy) => Boolean, msg: => Any): ConsistentHashingShardAllocationStrategy
    Implicit
    This member is added by an implicit conversion from ConsistentHashingShardAllocationStrategy toEnsuring[ConsistentHashingShardAllocationStrategy] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  11. def ensuring(cond: (ConsistentHashingShardAllocationStrategy) => Boolean): ConsistentHashingShardAllocationStrategy
    Implicit
    This member is added by an implicit conversion from ConsistentHashingShardAllocationStrategy toEnsuring[ConsistentHashingShardAllocationStrategy] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  12. def ensuring(cond: Boolean, msg: => Any): ConsistentHashingShardAllocationStrategy
    Implicit
    This member is added by an implicit conversion from ConsistentHashingShardAllocationStrategy toEnsuring[ConsistentHashingShardAllocationStrategy] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  13. def ensuring(cond: Boolean): ConsistentHashingShardAllocationStrategy
    Implicit
    This member is added by an implicit conversion from ConsistentHashingShardAllocationStrategy toEnsuring[ConsistentHashingShardAllocationStrategy] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  14. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  15. def equals(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef → Any
  16. final def getClass(): Class[_ <: AnyRef]
    Definition Classes
    AnyRef → Any
    Annotations
    @native() @HotSpotIntrinsicCandidate()
  17. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native() @HotSpotIntrinsicCandidate()
  18. final def isAGoodTimeToRebalance(regionEntries: Iterable[RegionEntry]): Boolean
    Attributes
    protected
    Definition Classes
    ClusterShardAllocationMixin
  19. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  20. def log: LoggingAdapter
    Attributes
    protected
  21. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  22. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native() @HotSpotIntrinsicCandidate()
  23. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native() @HotSpotIntrinsicCandidate()
  24. def rebalance(currentShardAllocations: Map[ActorRef, IndexedSeq[ShardId]], rebalanceInProgress: Set[ShardId]): Future[Set[ShardId]]

    Invoked periodically to decide which shards to rebalance to another location.

    Invoked periodically to decide which shards to rebalance to another location.

    currentShardAllocations

    all actor refs to ShardRegion and their current allocated shards, in the order they were allocated

    rebalanceInProgress

    set of shards that are currently being rebalanced, i.e. you should not include these in the returned set

    returns

    a Future of the shards to be migrated, may be empty to skip rebalance in this round

    Definition Classes
    ConsistentHashingShardAllocationStrategyShardAllocationStrategy
  25. final def regionEntriesFor(currentShardAllocations: AllocationMap): Iterable[RegionEntry]
    Attributes
    protected
    Definition Classes
    ClusterShardAllocationMixin
  26. def selfMember: Member
    Attributes
    protected
    Definition Classes
    ConsistentHashingShardAllocationStrategy → ClusterShardAllocationMixin
  27. def start(system: ActorSystem): Unit

    Called before any calls to allocate/rebalance.

    Called before any calls to allocate/rebalance. Do not block. If asynchronous actions are required they can be started here and delay the Futures returned by allocate/rebalance.

    Definition Classes
    ConsistentHashingShardAllocationStrategy → ActorSystemDependentAllocationStrategy
  28. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
    AnyRef
  29. def toString(): String
    Definition Classes
    AnyRef → Any
  30. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  31. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()
  32. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])

Deprecated Value Members

  1. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.Throwable]) @Deprecated @Deprecated
    Deprecated
  2. def formatted(fmtstr: String): String
    Implicit
    This member is added by an implicit conversion from ConsistentHashingShardAllocationStrategy toStringFormat[ConsistentHashingShardAllocationStrategy] 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): (ConsistentHashingShardAllocationStrategy, B)
    Implicit
    This member is added by an implicit conversion from ConsistentHashingShardAllocationStrategy toArrowAssoc[ConsistentHashingShardAllocationStrategy] 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 ClusterShardAllocationMixin

Inherited from ActorSystemDependentAllocationStrategy

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd fromConsistentHashingShardAllocationStrategy to any2stringadd[ConsistentHashingShardAllocationStrategy]

Inherited by implicit conversion StringFormat fromConsistentHashingShardAllocationStrategy to StringFormat[ConsistentHashingShardAllocationStrategy]

Inherited by implicit conversion Ensuring fromConsistentHashingShardAllocationStrategy to Ensuring[ConsistentHashingShardAllocationStrategy]

Inherited by implicit conversion ArrowAssoc fromConsistentHashingShardAllocationStrategy to ArrowAssoc[ConsistentHashingShardAllocationStrategy]

Ungrouped