org.apache.flink.runtime.state

Class DirectoryStateHandle

java.lang.Object

org.apache.flink.runtime.state.DirectoryStateHandle

All Implemented Interfaces:

Serializable, StateObject

public class DirectoryStateHandle
extends Object
implements StateObject

This state handle represents a directory. This class is, for example, used to represent the directory of RocksDB's native checkpoint directories for local recovery.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.flink.runtime.state.StateObject

StateObject.StateObjectLocation, StateObject.StateObjectSizeStatsCollector

Constructor Summary

Constructors

Constructor and Description
DirectoryStateHandle(Path directory, long directorySize)

Method Summary

Modifier and Type	Method and Description
void	collectSizeStats(StateObject.StateObjectSizeStatsCollector collector) Collects statistics about state size and location from the state object.
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)
static DirectoryStateHandle	forPathWithSize(Path directory)
Path	getDirectory()
long	getStateSize() Returns the size of the state in bytes.
int	hashCode()
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

DirectoryStateHandle

public DirectoryStateHandle(@Nonnull
                            Path directory,
                            long directorySize)

Method Detail

forPathWithSize

public static DirectoryStateHandle forPathWithSize(@Nonnull
                                                   Path directory)

discardState

public void discardState()
                  throws IOException

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 anymore.

Specified by:

discardState in interface StateObject

Throws:

IOException

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.

collectSizeStats

public void collectSizeStats(StateObject.StateObjectSizeStatsCollector collector)

Description copied from interface: StateObject

Collects statistics about state size and location from the state object.

Specified by:

collectSizeStats in interface StateObject

Parameters:

collector - the statistics collector.

getDirectory

@Nonnull
public Path getDirectory()

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