Class SegmentFileStateHandle
- java.lang.Object
-
- org.apache.flink.runtime.state.filemerging.SegmentFileStateHandle
-
- All Implemented Interfaces:
Serializable
,StateObject
,StreamStateHandle
- Direct Known Subclasses:
EmptySegmentFileStateHandle
public class SegmentFileStateHandle extends Object implements StreamStateHandle
FileStateHandle
for state that was written to a file segment. ASegmentFileStateHandle
represents aLogicalFile
, which has already been written to a segment in a physical file.- See Also:
- Serialized Form
-
-
Nested Class Summary
-
Nested classes/interfaces inherited from interface org.apache.flink.runtime.state.StateObject
StateObject.StateObjectLocation, StateObject.StateObjectSizeStatsCollector
-
-
Field Summary
Fields Modifier and Type Field Description protected long
stateSize
The size of the state in the file.
-
Constructor Summary
Constructors Constructor Description SegmentFileStateHandle(Path filePath, long startPos, long stateSize, CheckpointedStateScope scope, LogicalFile.LogicalFileId fileId)
Creates a new segment file state for the given file path.
-
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Optional<byte[]>
asBytesIfInMemory()
void
collectSizeStats(StateObject.StateObjectSizeStatsCollector collector)
Collects statistics about state size and location from the state object.void
discardState()
This method should be empty, so that JM is not in charge of the lifecycle of files in a file-merging checkpoint.boolean
equals(Object o)
Path
getFilePath()
Gets the path where this handle's state is stored.LogicalFile.LogicalFileId
getLogicalFileId()
CheckpointedStateScope
getScope()
long
getStartPos()
long
getStateSize()
Returns the size of the state in bytes.PhysicalStateHandleID
getStreamStateHandleID()
int
hashCode()
FSDataInputStream
openInputStream()
Returns anFSDataInputStream
that can be used to read back the data that was previously written to the stream.String
toString()
-
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
-
Methods inherited from interface org.apache.flink.runtime.state.StreamStateHandle
maybeGetPath
-
-
-
-
Constructor Detail
-
SegmentFileStateHandle
public SegmentFileStateHandle(Path filePath, long startPos, long stateSize, CheckpointedStateScope scope, LogicalFile.LogicalFileId fileId)
Creates a new segment file state for the given file path.- Parameters:
filePath
- The path to the file that stores the state.startPos
- Start position of the segment in the physical file.stateSize
- Size of the segment.scope
- The state's scope, whether it is exclusive or shared.fileId
- The corresponding logical file id.
-
-
Method Detail
-
discardState
public void discardState()
This method should be empty, so that JM is not in charge of the lifecycle of files in a file-merging checkpoint.- Specified by:
discardState
in interfaceStateObject
-
getFilePath
public Path getFilePath()
Gets the path where this handle's state is stored.- Returns:
- The path where this handle's state is stored.
-
openInputStream
public FSDataInputStream openInputStream() throws IOException
Description copied from interface:StreamStateHandle
Returns anFSDataInputStream
that can be used to read back the data that was previously written to the stream.- Specified by:
openInputStream
in interfaceStreamStateHandle
- Throws:
IOException
-
asBytesIfInMemory
public Optional<byte[]> asBytesIfInMemory()
- Specified by:
asBytesIfInMemory
in interfaceStreamStateHandle
- Returns:
- Content of this handle as bytes array if it is already in memory.
-
getStreamStateHandleID
public PhysicalStateHandleID getStreamStateHandleID()
- Specified by:
getStreamStateHandleID
in interfaceStreamStateHandle
- Returns:
- a unique identifier of this handle.
-
getStartPos
public long getStartPos()
-
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 return0
.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 interfaceStateObject
- 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 interfaceStateObject
- Parameters:
collector
- the statistics collector.
-
getScope
public CheckpointedStateScope getScope()
-
getLogicalFileId
public LogicalFile.LogicalFileId getLogicalFileId()
-
-