org.mapdb

Class WriteAheadLog

java.lang.Object

org.mapdb.WriteAheadLog

public class WriteAheadLog
extends Object

WAL shared between StoreWAL and StoreAppend

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	WriteAheadLog.WALReplay

Field Summary

Fields

Modifier and Type	Field and Description
protected Volume	curVol
protected long	featureBitMap
protected long	fileNum
protected long	fileOffset
protected ReentrantLock	fileOffsetLock
protected static int	I_BYTE_ARRAY
protected static int	I_COMMIT
protected static int	I_EOF
protected static int	I_LONG
protected static int	I_PREALLOCATE
protected static int	I_RECORD
protected static int	I_ROLLBACK
protected static int	I_SKIP_MANY
protected static int	I_SKIP_SINGLE
protected static int	I_TOMBSTONE
protected int	lastChecksum
protected long	lastChecksumOffset
protected static long	MAX_FILE_RESERVE
protected static long	MAX_FILE_SIZE
static WriteAheadLog.WALReplay	NOREPLAY does nothing
protected int	pointerFileBites
protected long	pointerFileMask
protected int	pointerOffsetBites
protected long	pointerOffsetMask
protected int	pointerSizeBites
protected long	pointerSizeMask
protected List<Volume>	volumes
protected static int	WAL_HEADER 4 byte file header
protected static long	WAL_SEAL
protected static int	WAL_STORE_VERSION 2 byte store version
protected List<Volume>	walRec record WALs, store recid-record pairs.

Constructor Summary

Constructors

Constructor and Description
WriteAheadLog(String fileName)
WriteAheadLog(String fileName, Volume.VolumeFactory volumeFactory, long featureBitMap)

Method Summary

Methods

Modifier and Type	Method and Description
protected long	allocate(int reqSize, int optSize) Allocate space in WAL
protected int	checksum(Volume vol, long startOffset, long endOffset)
void	close()
void	commit()
void	destroyWalFiles()
protected void	ensureFileReady(boolean addressable)
boolean	fileLoad()
protected void	fileOffsetSet(long fileOffset)
long	getNumberOfFiles()
protected String	getWalFileName(String ext)
void	initFailedCloseFiles()
void	rollback()
void	seal()
void	startNextFile()
void	sync()
DataInput	walGetByteArray(long walPointer) Retrieve DataInput from WAL.
byte[]	walGetByteArray2(long walPointer) Retrieve byte[] from WAL.
byte[]	walGetRecord(long walPointer, long expectedRecid)
protected long	walPointer(long size, long fileNum, long offset)
protected long	walPointerToFileNum(long walPointer)
protected long	walPointerToOffset(long walPointer)
protected int	walPointerToSize(long walPointer)
long	walPutByteArray(long offset, byte[] buf, int bufPos, int size) Puts instruction into WAL.
protected void	walPutLong(long offset, long value) Put 8 byte long into WAL.
void	walPutPreallocate(long recid)
long	walPutRecord(long recid, byte[] buf, int bufPos, int size)
void	walPutTombstone(long recid)

Methods inherited from class java.lang.Object

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

Field Detail

WAL_STORE_VERSION

protected static final int WAL_STORE_VERSION

2 byte store version

See Also:

Constant Field Values

WAL_HEADER

protected static final int WAL_HEADER

4 byte file header

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Constant Field Values

WAL_SEAL

protected static final long WAL_SEAL

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Constant Field Values

I_EOF

protected static final int I_EOF

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Constant Field Values

I_LONG

protected static final int I_LONG

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Constant Field Values

I_BYTE_ARRAY

protected static final int I_BYTE_ARRAY

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Constant Field Values

I_SKIP_MANY

protected static final int I_SKIP_MANY

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Constant Field Values

I_SKIP_SINGLE

protected static final int I_SKIP_SINGLE

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Constant Field Values

I_RECORD

protected static final int I_RECORD

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Constant Field Values

I_TOMBSTONE

protected static final int I_TOMBSTONE

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Constant Field Values

I_PREALLOCATE

protected static final int I_PREALLOCATE

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Constant Field Values

I_COMMIT

protected static final int I_COMMIT

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Constant Field Values

I_ROLLBACK

protected static final int I_ROLLBACK

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Constant Field Values

MAX_FILE_SIZE

protected static final long MAX_FILE_SIZE

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Constant Field Values

MAX_FILE_RESERVE

protected static final long MAX_FILE_RESERVE

See Also:

Constant Field Values

featureBitMap

protected final long featureBitMap

pointerOffsetBites

protected final int pointerOffsetBites

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Constant Field Values

pointerOffsetMask

protected final long pointerOffsetMask

pointerSizeBites

protected final int pointerSizeBites

See Also:

Constant Field Values

pointerSizeMask

protected final long pointerSizeMask

pointerFileBites

protected final int pointerFileBites

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Constant Field Values

pointerFileMask

protected final long pointerFileMask

lastChecksum

protected int lastChecksum

lastChecksumOffset

protected long lastChecksumOffset

NOREPLAY

public static final WriteAheadLog.WALReplay NOREPLAY

does nothing

fileOffset

protected volatile long fileOffset

fileOffsetLock

protected ReentrantLock fileOffsetLock

volumes

protected final List<Volume> volumes

walRec

protected final List<Volume> walRec

record WALs, store recid-record pairs. Created during compaction when memory allocator is not available

curVol

protected Volume curVol

fileNum

protected long fileNum

Constructor Detail

WriteAheadLog

public WriteAheadLog(String fileName,
             Volume.VolumeFactory volumeFactory,
             long featureBitMap)

WriteAheadLog

public WriteAheadLog(String fileName)

Method Detail

initFailedCloseFiles

public void initFailedCloseFiles()

close

public void close()

seal

public void seal()

startNextFile

public void startNextFile()

rollback

public void rollback()

commit

public void commit()

checksum

protected int checksum(Volume vol,
           long startOffset,
           long endOffset)

fileLoad

public boolean fileLoad()

sync

public void sync()

allocate

protected long allocate(int reqSize,
            int optSize)

Allocate space in WAL

Parameters:

reqSize - space which can not cross page boundaries

optSize - space which can cross page boundaries

Returns:

allocated fileOffset

fileOffsetSet

protected void fileOffsetSet(long fileOffset)

destroyWalFiles

public void destroyWalFiles()

getWalFileName

protected String getWalFileName(String ext)

getNumberOfFiles

public long getNumberOfFiles()

walGetByteArray

public DataInput walGetByteArray(long walPointer)

Retrieve DataInput from WAL. This data were written by walPutByteArray(long, byte[], int, int)

Parameters:

walPointer - pointer returned by walPutByteArray(long, byte[], int, int)

Returns:

DataInput

walGetByteArray2

public byte[] walGetByteArray2(long walPointer)

Retrieve byte[] from WAL. This data were written by walPutByteArray(long, byte[], int, int)

Parameters:

walPointer - pointer returned by walPutByteArray(long, byte[], int, int)

Returns:

DataInput

walPointerToOffset

protected long walPointerToOffset(long walPointer)

walPointerToFileNum

protected long walPointerToFileNum(long walPointer)

walPointerToSize

protected int walPointerToSize(long walPointer)

walGetRecord

public byte[] walGetRecord(long walPointer,
                  long expectedRecid)

walPutByteArray

public long walPutByteArray(long offset,
                   byte[] buf,
                   int bufPos,
                   int size)

Puts instruction into WAL. It should write part of byte[] at given offset. This value returns pointer to WAL, which can be used to retrieve data back with walGetByteArray(long). Pointer is composed of file number, and offset in WAL file.

Parameters:

offset - where data will be written in main store, after WAL replay (6 bytes)

buf - byte array of data

bufPos - starting position within byte array

size - number of bytes to take from byte array

Returns:

walPointer

protected long walPointer(long size,
              long fileNum,
              long offset)

walPutRecord

public long walPutRecord(long recid,
                byte[] buf,
                int bufPos,
                int size)

walPutLong

protected void walPutLong(long offset,
              long value)

Put 8 byte long into WAL.

Parameters:

offset - where data will be written in main store, after WAL replay (6 bytes)

value -

ensureFileReady

protected void ensureFileReady(boolean addressable)

walPutTombstone

public void walPutTombstone(long recid)

walPutPreallocate

public void walPutPreallocate(long recid)