org.apache.cassandra.db.commitlog

Class CommitLogSegment

java.lang.Object

org.apache.cassandra.db.commitlog.CommitLogSegment

Direct Known Subclasses:

FileDirectSegment, MemoryMappedSegment

public abstract class CommitLogSegment
extends java.lang.Object

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	CommitLogSegment.Allocation A simple class for tracking information about the portion of a segment that has been allocated to a log write.
static class	CommitLogSegment.CDCState
static class	CommitLogSegment.CommitLogSegmentFileComparator

Field Summary

Fields

Modifier and Type	Field and Description
CommitLogDescriptor	descriptor
static int	ENTRY_OVERHEAD_SIZE
long	id
protected AbstractCommitLogSegmentManager	manager

Method Summary

Modifier and Type	Method and Description
protected java.util.Map<java.lang.String,java.lang.String>	additionalHeaderParameters() Provide any additional header data that should be stored in the CommitLogDescriptor.
boolean	contains(CommitLogPosition context) Check to see if a certain CommitLogPosition is contained by this segment file.
long	contentSize()
static <K> void	coverInMap(java.util.concurrent.ConcurrentMap<K,IntegerInterval> map, K key, int value)
java.lang.String	dirtyString()
java.io.File	getCDCFile()
java.io.File	getCDCIndexFile()
CommitLogSegment.CDCState	getCDCState()
CommitLogPosition	getCurrentCommitLogPosition()
java.util.Collection<TableId>	getDirtyTableIds()
java.lang.String	getName()
java.lang.String	getPath()
protected void	internalClose() Close the segment file.
boolean	isStillAllocating()
boolean	isUnused()
void	markClean(TableId tableId, CommitLogPosition startPosition, CommitLogPosition endPosition) Marks the ColumnFamily specified by id as clean for this log segment.
abstract long	onDiskSize()
void	setCDCState(CommitLogSegment.CDCState newState) Change the current cdcState on this CommitLogSegment.
java.lang.String	toString()
static void	writeCDCIndexFile(CommitLogDescriptor desc, int offset, boolean complete) We persist the offset of the last data synced to disk so clients can parse only durable data if they choose.
protected static void	writeSyncMarker(long id, java.nio.ByteBuffer buffer, int offset, int filePos, int nextMarker) Create a sync marker to delineate sections of the commit log, typically created on each sync of the file.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

ENTRY_OVERHEAD_SIZE

public static final int ENTRY_OVERHEAD_SIZE

See Also:

Constant Field Values

id

public final long id

manager

protected final AbstractCommitLogSegmentManager manager

descriptor

public final CommitLogDescriptor descriptor

Method Detail

additionalHeaderParameters

protected java.util.Map<java.lang.String,java.lang.String> additionalHeaderParameters()

Provide any additional header data that should be stored in the CommitLogDescriptor.

writeCDCIndexFile

public static void writeCDCIndexFile(CommitLogDescriptor desc,
                                     int offset,
                                     boolean complete)

We persist the offset of the last data synced to disk so clients can parse only durable data if they choose. Data in shared / memory-mapped buffers reflects un-synced data so we need an external sentinel for clients to read to determine actual durable data persisted.

writeSyncMarker

protected static void writeSyncMarker(long id,
                                      java.nio.ByteBuffer buffer,
                                      int offset,
                                      int filePos,
                                      int nextMarker)

Create a sync marker to delineate sections of the commit log, typically created on each sync of the file. The sync marker consists of a file pointer to where the next sync marker should be (effectively declaring the length of this section), as well as a CRC value.

Parameters:

buffer - buffer in which to write out the sync marker.

offset - Offset into the buffer at which to write the sync marker.

filePos - The current position in the target file where the sync marker will be written (most likely different from the buffer position).

nextMarker - The file position of where the next sync marker should be.

isStillAllocating

public boolean isStillAllocating()

getCurrentCommitLogPosition

public CommitLogPosition getCurrentCommitLogPosition()

Returns:

the current CommitLogPosition for this log segment

getPath

public java.lang.String getPath()

Returns:

the file path to this segment

getName

public java.lang.String getName()

Returns:

the file name of this segment

getCDCFile

public java.io.File getCDCFile()

Returns:

a File object representing the CDC directory and this file name for hard-linking

getCDCIndexFile

public java.io.File getCDCIndexFile()

Returns:

a File object representing the CDC Index file holding the offset and completion status of this segment

internalClose

protected void internalClose()

Close the segment file. Do not call from outside this class, use syncAndClose() instead.

coverInMap

public static <K> void coverInMap(java.util.concurrent.ConcurrentMap<K,IntegerInterval> map,
                                  K key,
                                  int value)

markClean

public void markClean(TableId tableId,
                      CommitLogPosition startPosition,
                      CommitLogPosition endPosition)

Marks the ColumnFamily specified by id as clean for this log segment. If the given context argument is contained in this file, it will only mark the CF as clean if no newer writes have taken place.

Parameters:

tableId - the table that is now clean

startPosition - the start of the range that is clean

endPosition - the end of the range that is clean

getDirtyTableIds

public java.util.Collection<TableId> getDirtyTableIds()

Returns:

a collection of dirty CFIDs for this segment file.

isUnused

public boolean isUnused()

Returns:

true if this segment is unused and safe to recycle or delete

contains

public boolean contains(CommitLogPosition context)

Check to see if a certain CommitLogPosition is contained by this segment file.

Parameters:

context - the commit log segment position to be checked

Returns:

true if the commit log segment position is contained by this segment file.

dirtyString

public java.lang.String dirtyString()

onDiskSize

public abstract long onDiskSize()

contentSize

public long contentSize()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getCDCState

public CommitLogSegment.CDCState getCDCState()

setCDCState

public void setCDCState(CommitLogSegment.CDCState newState)

Change the current cdcState on this CommitLogSegment. There are some restrictions on state transitions and this method is idempotent.