org.apache.cassandra.db.commitlog

Class CompressedSegment

java.lang.Object

org.apache.cassandra.db.commitlog.CommitLogSegment

org.apache.cassandra.db.commitlog.FileDirectSegment

org.apache.cassandra.db.commitlog.CompressedSegment

public class CompressedSegment
extends FileDirectSegment

Compressed commit log segment. Provides an in-memory buffer for the mutation threads. On sync compresses the written section of the buffer and writes it to the destination channel. The format of the compressed commit log is as follows: - standard commit log header (as written by CommitLogDescriptor.writeHeader(ByteBuffer, CommitLogDescriptor)) - a series of 'sync segments' that are written every time the commit log is sync()'ed -- a sync section header, see CommitLogSegment.writeSyncMarker(ByteBuffer, int, int, int) -- total plain text length for this section -- a block of compressed data

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.cassandra.db.commitlog.CommitLogSegment

CommitLogSegment.CommitLogSegmentFileComparator

Field Summary

Fields inherited from class org.apache.cassandra.db.commitlog.FileDirectSegment

reusableBufferHolder

Fields inherited from class org.apache.cassandra.db.commitlog.CommitLogSegment

descriptor, ENTRY_OVERHEAD_SIZE, id

Method Summary

Modifier and Type	Method and Description
long	onDiskSize()

Methods inherited from class org.apache.cassandra.db.commitlog.FileDirectSegment

internalClose

Methods inherited from class org.apache.cassandra.db.commitlog.CommitLogSegment

additionalHeaderParameters, contains, contentSize, dirtyString, getContext, getDirtyCFIDs, getName, getPath, isStillAllocating, isUnused, markClean, toString, writeSyncMarker

Methods inherited from class java.lang.Object

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

Method Detail

onDiskSize

public long onDiskSize()

Specified by:

onDiskSize in class CommitLogSegment