org.apache.flink.runtime.state

Class KeyGroupsStateHandle

java.lang.Object

org.apache.flink.runtime.state.KeyGroupsStateHandle

All Implemented Interfaces:

Serializable, CompositeStateHandle, KeyedStateHandle, StateObject, StreamStateHandle

public class KeyGroupsStateHandle
extends Object
implements StreamStateHandle, KeyedStateHandle

A handle to the partitioned stream operator state after it has been checkpointed. This state consists of a range of key group snapshots. A key group is subset of the available key space. The key groups are identified by their key group indices.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
KeyGroupsStateHandle(KeyGroupRangeOffsets groupRangeOffsets, StreamStateHandle streamStateHandle)

Method Summary

Modifier and Type	Method and Description
Optional<byte[]>	asBytesIfInMemory()
void	discardState() Discards the state referred to and solemnly owned by this handle, to free up resources in the persistent storage.
boolean	equals(Object o)
StreamStateHandle	getDelegateStateHandle()
KeyGroupRangeOffsets	getGroupRangeOffsets()
KeyGroupsStateHandle	getIntersection(KeyGroupRange keyGroupRange) Returns a state over a range that is the intersection between this handle's key-group range and the provided key-group range.
KeyGroupRange	getKeyGroupRange() Returns the range of the key groups contained in the state.
long	getOffsetForKeyGroup(int keyGroupId)
long	getStateSize() Returns the size of the state in bytes.
int	hashCode()
FSDataInputStream	openInputStream() Returns an FSDataInputStream that can be used to read back the data that was previously written to the stream.
void	registerSharedStates(SharedStateRegistry stateRegistry) Register both newly created and already referenced shared states in the given SharedStateRegistry.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

KeyGroupsStateHandle

public KeyGroupsStateHandle(KeyGroupRangeOffsets groupRangeOffsets,
                            StreamStateHandle streamStateHandle)

Parameters:

groupRangeOffsets - range of key-group ids that in the state of this handle

streamStateHandle - handle to the actual state of the key-groups

Method Detail

getGroupRangeOffsets

public KeyGroupRangeOffsets getGroupRangeOffsets()

Returns:

the internal key-group range to offsets metadata

getDelegateStateHandle

public StreamStateHandle getDelegateStateHandle()

Returns:

The handle to the actual states

getOffsetForKeyGroup

public long getOffsetForKeyGroup(int keyGroupId)

Parameters:

keyGroupId - the id of a key-group. the id must be contained in the range of this handle.

Returns:

offset to the position of data for the provided key-group in the stream referenced by this state handle

getIntersection

public KeyGroupsStateHandle getIntersection(KeyGroupRange keyGroupRange)

Description copied from interface: KeyedStateHandle

Returns a state over a range that is the intersection between this handle's key-group range and the provided key-group range.

Specified by:

getIntersection in interface KeyedStateHandle

Parameters:

keyGroupRange - a key group range to intersect.

Returns:

key-group state over a range that is the intersection between this handle's key-group range and the provided key-group range.

getKeyGroupRange

public KeyGroupRange getKeyGroupRange()

Description copied from interface: KeyedStateHandle

Returns the range of the key groups contained in the state.

Specified by:

getKeyGroupRange in interface KeyedStateHandle

registerSharedStates

public void registerSharedStates(SharedStateRegistry stateRegistry)

Description copied from interface: CompositeStateHandle

Register both newly created and already referenced shared states in the given SharedStateRegistry. This method is called when the checkpoint successfully completes or is recovered from failures.

After this is completed, newly created shared state is considered as published is no longer owned by this handle. This means that it should no longer be deleted as part of calls to StateObject.discardState(). Instead, StateObject.discardState() will trigger an unregistration from the registry.

Specified by:

registerSharedStates in interface CompositeStateHandle

Parameters:

stateRegistry - The registry where shared states are registered.

discardState

public void discardState()
                  throws Exception

Description copied from interface: StateObject

Discards the state referred to and solemnly owned by this handle, to free up resources in the persistent storage. This method is called when the state represented by this object will not be used any more.

Specified by:

discardState in interface StateObject

Throws:

Exception

getStateSize

public long getStateSize()

Description copied from interface: StateObject

Returns the size of the state in bytes. If the size is not known, this method should return 0.

The values produced by this method are only used for informational purposes and for metrics/monitoring. If this method returns wrong values, the checkpoints and recovery will still behave correctly. However, efficiency may be impacted (wrong space pre-allocation) and functionality that depends on metrics (like monitoring) will be impacted.

Note for implementors: This method should not perform any I/O operations while obtaining the state size (hence it does not declare throwing an IOException). Instead, the state size should be stored in the state object, or should be computable from the state stored in this object. The reason is that this method is called frequently by several parts of the checkpointing and issuing I/O requests from this method accumulates a heavy I/O load on the storage system at higher scale.

Specified by:

getStateSize in interface StateObject

Returns:

Size of the state in bytes.

openInputStream

public FSDataInputStream openInputStream()
                                  throws IOException

Description copied from interface: StreamStateHandle

Returns an FSDataInputStream that can be used to read back the data that was previously written to the stream.

Specified by:

openInputStream in interface StreamStateHandle

Throws:

IOException

asBytesIfInMemory

public Optional<byte[]> asBytesIfInMemory()

Specified by:

asBytesIfInMemory in interface StreamStateHandle

Returns:

Content of this handle as bytes array if it is already in memory.

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object