Package org.infinispan.distribution.ch.impl

Class ScatteredConsistentHash

java.lang.Object

org.infinispan.distribution.ch.impl.AbstractConsistentHash

org.infinispan.distribution.ch.impl.ScatteredConsistentHash

All Implemented Interfaces:

ConsistentHash

@Immutable
public class ScatteredConsistentHash
extends AbstractConsistentHash

CH used by scattered caches. Allows no owners for segments (until the CH is balanced). We cannot have an owner for each segment assigned all the time, because after one node crashes, ConsistentHashFactory.updateMembers(CH, java.util.List<org.infinispan.remoting.transport.Address>, java.util.Map<org.infinispan.remoting.transport.Address, java.lang.Float>) is called and the result is sent in CH_UPDATE. Such topology is installed and later during rebalance, a diff of segments between the installed and new (rebalancing) topology is computed. If we assigned all the owners right in updateMembers, this diff would be empty.

Since:

9.1

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ScatteredConsistentHash.Externalizer

Field Summary

Fields inherited from class org.infinispan.distribution.ch.impl.AbstractConsistentHash

capacityFactors, hashFunction, members, segmentSize, STATE_CAPACITY_FACTOR, STATE_CAPACITY_FACTORS, STATE_NUM_SEGMENTS

Constructor Summary

Constructors

Constructor	Description
ScatteredConsistentHash(org.infinispan.commons.hash.Hash hashFunction, int numSegments, List<Address> members, Map<Address,Float> capacityFactors, Address[] segmentOwners, boolean isRebalanced)

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object o)
int	getNumOwners()
int	getNumSegments()
Set<Integer>	getPrimarySegmentsForOwner(Address owner)	Returns the segments that this cache member is the primary owner for.
String	getRoutingTableAsString()	Returns a string containing all the segments and their associated addresses.
Set<Integer>	getSegmentsForOwner(Address owner)	Returns the segments owned by a cache member.
int	hashCode()
boolean	isSegmentLocalToNode(Address nodeAddress, int segmentId)	Check if a segment is local to a given member.
Set<Address>	locateAllOwners(Collection<Object> keys)
List<Address>	locateOwnersForSegment(int segmentId)
Address	locatePrimaryOwnerForSegment(int segmentId)
ConsistentHash	remapAddresses(UnaryOperator<Address> remapper)	Returns a new ConsistentHash with the addresses remapped according to the provided UnaryOperator.
void	toScopedState(ScopedPersistentState state)	Writes this ConsistentHash to the specified scoped state.
String	toString()
ScatteredConsistentHash	union(ScatteredConsistentHash sch2)	Prefers owners from the second hash -> effectively this will make pendingCH == unionCH (I think)

Methods inherited from class org.infinispan.distribution.ch.impl.AbstractConsistentHash

checkSameHashAndSegments, getCapacityFactors, getHashFunction, getMembers, getNormalizedHash, getSegment, isKeyLocalToNode, mergeLists, parseCapacityFactors, parseHashFunction, parseMembers, parseNumSegments, remapCapacityFactors, remapMembers, unionCapacityFactors

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.infinispan.distribution.ch.ConsistentHash

isReplicated, locateOwners, locatePrimaryOwner

Constructor Detail

ScatteredConsistentHash

public ScatteredConsistentHash(org.infinispan.commons.hash.Hash hashFunction,
                               int numSegments,
                               List<Address> members,
                               Map<Address,Float> capacityFactors,
                               Address[] segmentOwners,
                               boolean isRebalanced)

Method Detail

getNumSegments

public int getNumSegments()

Returns:

The actual number of hash space segments. Note that it may not be the same as the number of segments passed in at creation time.

getSegmentsForOwner

public Set<Integer> getSegmentsForOwner(Address owner)

Description copied from interface: ConsistentHash

Returns the segments owned by a cache member.

Parameters:

owner - the address of the member

Returns:

a non-null set of segment IDs, may or may not be unmodifiable, which shouldn't be modified by caller. The set is empty if owner is not a member of the consistent hash.

getPrimarySegmentsForOwner

public Set<Integer> getPrimarySegmentsForOwner(Address owner)

Description copied from interface: ConsistentHash

Returns the segments that this cache member is the primary owner for.

Parameters:

owner - the address of the member

Returns:

a non-null set of segment IDs, may or may not be unmodifiable, which shouldn't be modified by caller. The set is empty if owner is not a member of the consistent hash.

locateOwnersForSegment

public List<Address> locateOwnersForSegment(int segmentId)

Returns:

All the nodes that own a given hash space segment, first address is the primary owner. The returned list is unmodifiable.

locatePrimaryOwnerForSegment

public Address locatePrimaryOwnerForSegment(int segmentId)

Returns:

The primary owner of a given hash space segment. This is equivalent to locateOwnersForSegment(segmentId).get(0) but is more efficient

getNumOwners

public int getNumOwners()

Returns:

The configured number of owners. Note that the actual number of owners of each key may be different.

locateAllOwners

public Set<Address> locateAllOwners(Collection<Object> keys)

isSegmentLocalToNode

public boolean isSegmentLocalToNode(Address nodeAddress,
                                    int segmentId)

Description copied from interface: ConsistentHash

Check if a segment is local to a given member.

Implementation note: normally key-based method are implemented based on segment-based methods. Here, however, we need a default implementation for the segment-based method for backwards-compatibility reasons.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object o)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object

getRoutingTableAsString

public String getRoutingTableAsString()

Description copied from interface: ConsistentHash

Returns a string containing all the segments and their associated addresses.

union

public ScatteredConsistentHash union(ScatteredConsistentHash sch2)

Prefers owners from the second hash -> effectively this will make pendingCH == unionCH (I think)

toScopedState

public void toScopedState(ScopedPersistentState state)

Description copied from interface: ConsistentHash

Writes this ConsistentHash to the specified scoped state. Before invoking this method, the ConsistentHash addresses will have to be replaced with their corresponding PersistentUUIDs

Specified by:

toScopedState in interface ConsistentHash

Overrides:

toScopedState in class AbstractConsistentHash

Parameters:

state - the state to which this ConsistentHash will be written

remapAddresses

public ConsistentHash remapAddresses(UnaryOperator<Address> remapper)

Description copied from interface: ConsistentHash

Returns a new ConsistentHash with the addresses remapped according to the provided UnaryOperator. If an address cannot me remapped (i.e. the remapper returns null) this method should return null.

Parameters:

remapper - the remapper which given an address replaces it with another one

Returns:

the remapped ConsistentHash or null if one of the remapped addresses is null