org.h2.mvstore

Class RandomAccessStore

java.lang.Object

org.h2.mvstore.FileStore<org.h2.mvstore.SFChunk>

org.h2.mvstore.RandomAccessStore

Direct Known Subclasses:

OffHeapStore, SingleFileStore

public abstract class RandomAccessStore
extends FileStore<org.h2.mvstore.SFChunk>

Class RandomAccessStore.

• 4/5/20 2:51 PM initial creation

Nested Class Summary

Nested classes/interfaces inherited from class org.h2.mvstore.FileStore

FileStore.PageSerializationManager

Field Summary

Fields

Modifier and Type	Field and Description
protected FreeSpaceBitSet	freeSpace The free spaces between the chunks.

Fields inherited from class org.h2.mvstore.FileStore

lastChunk, META_ID_KEY, PIPE_LENGTH, readBytes, readCount, recoveryMode, saveChunkLock, storeHeader, writeBytes, writeCount

Constructor Summary

Constructors

Constructor and Description
RandomAccessStore(java.util.Map<java.lang.String,java.lang.Object> config)

Method Summary

Modifier and Type	Method and Description
protected void	adjustStoreToLastChunk() Make persistent changes after lastChunk was reset
protected void	allocateChunkSpace(org.h2.mvstore.SFChunk chunk, WriteBuffer buff) Allocate logical space and assign position of the buffer within the store.
void	clear() Mark the file as empty.
void	compactMoveChunks(int targetFillRate, long moveSize, MVStore mvStore) Compact the store by moving all chunks next to each other, if there is free space between chunks.
protected void	compactStore(int thresholdFillRate, long maxCompactTime, int maxWriteSize, MVStore mvStore) Compact store file, that is, compact blocks that have a low fill rate, and move chunks next to each other.
protected org.h2.mvstore.SFChunk	createChunk(int newChunkId)
protected org.h2.mvstore.SFChunk	createChunk(java.util.Map<java.lang.String,java.lang.String> map)
org.h2.mvstore.SFChunk	createChunk(java.lang.String s) Build a Chunk from the given string.
protected void	doHousekeeping(MVStore mvStore)
protected void	free(long pos, int length) Mark the space as free.
protected void	freeChunkSpace(java.lang.Iterable<org.h2.mvstore.SFChunk> chunks) Mark the space occupied by specified chunks as free.
protected long	getAfterLastBlock_()
int	getFillRate()
int	getMovePriority(int block) Calculates relative "priority" for chunk to be moved.
java.util.Collection<org.h2.mvstore.SFChunk>	getRewriteCandidates()
protected void	initializeStoreHeader(long time)
boolean	isSpaceReused()
void	markUsed(long pos, int length) Mark the space as in use.
protected void	readStoreHeader(boolean recoveryMode)
void	setReuseSpace(boolean reuseSpace)
boolean	shouldSaveNow(int unsavedMemory, int autoCommitMemory) Decision about autocommit is delegated to store
protected void	shrinkStoreIfPossible(int minPercent) Shrink the store if possible, and if at least a given percentage can be saved.
protected abstract void	truncate(long size)
protected boolean	validateFileLength(java.lang.String msg)
protected void	writeChunk(org.h2.mvstore.SFChunk chunk, WriteBuffer buffer) Write buffer associated with chunk into store at chunk's allocated position
protected void	writeCleanShutdownMark() Performs final preparation before store is closed normally

Methods inherited from class org.h2.mvstore.FileStore

accountForRemovedPage, backup, bind, close, compact, compactStore, deregisterMapRoot, discoverChunk, dropUnusedChunks, executeFileStoreOperation, findLastChunkWithCompleteValidChunkSet, getAutoCommitDelay, getAutoCompactFillRate, getCacheHitRatio, getCacheSize, getCacheSizeUsed, getChunks, getChunksFillRate, getChunksFromLayoutMap, getCreationTime, getDefaultRetentionTime, getFileName, getLayoutMap, getMaxPageSize, getMetaMapId, getMvStore, getReadBytes, getReadCount, getRetentionTime, getRootPos, getStoreHeader, getTocCacheHitRatio, getWriteBuffer, getWriteCount, hasChangesSince, hasPersistentData, init, initializeCommonHeaderAttributes, isIdle, isKnownVersion, isReadOnly, isRegularMap, lastChunkVersion, open, open, populateInfo, processCommonHeaderAttributes, readChunkFooter, readChunkHeaderAndFooter, readChunkHeaderOptionally, readChunkHeaderOptionally, readFully, readFully, registerDeadChunk, releaseWriteBuffer, rewriteChunks, rollbackTo, saveChunkMetadataChanges, setAutoCommitDelay, setCacheSize, setLastChunk, setRetentionTime, setSize, size, start, stop, store, sync, writeCleanShutdown, writeFully

Methods inherited from class java.lang.Object

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

Field Detail

freeSpace

protected final FreeSpaceBitSet freeSpace

The free spaces between the chunks. The first block to use is block 2 (the first two blocks are the store header).

Constructor Detail

RandomAccessStore

public RandomAccessStore(java.util.Map<java.lang.String,java.lang.Object> config)

Method Detail

createChunk

protected final org.h2.mvstore.SFChunk createChunk(int newChunkId)

Specified by:

createChunk in class FileStore<org.h2.mvstore.SFChunk>

createChunk

public org.h2.mvstore.SFChunk createChunk(java.lang.String s)

Description copied from class: FileStore

Build a Chunk from the given string.

Specified by:

createChunk in class FileStore<org.h2.mvstore.SFChunk>

Parameters:

s - the string

Returns:

the Chunk created

createChunk

protected org.h2.mvstore.SFChunk createChunk(java.util.Map<java.lang.String,java.lang.String> map)

Specified by:

createChunk in class FileStore<org.h2.mvstore.SFChunk>

markUsed

public void markUsed(long pos,
                     int length)

Mark the space as in use.

Specified by:

markUsed in class FileStore<org.h2.mvstore.SFChunk>

Parameters:

pos - the position in bytes

length - the number of bytes

shouldSaveNow

public boolean shouldSaveNow(int unsavedMemory,
                             int autoCommitMemory)

Description copied from class: FileStore

Decision about autocommit is delegated to store

Specified by:

shouldSaveNow in class FileStore<org.h2.mvstore.SFChunk>

Parameters:

unsavedMemory - amount of unsaved memory, so far

autoCommitMemory - configured limit on amount of unsaved memory

Returns:

true if commit should happen now

isSpaceReused

public boolean isSpaceReused()

Overrides:

isSpaceReused in class FileStore<org.h2.mvstore.SFChunk>

setReuseSpace

public void setReuseSpace(boolean reuseSpace)

Overrides:

setReuseSpace in class FileStore<org.h2.mvstore.SFChunk>

freeChunkSpace

protected void freeChunkSpace(java.lang.Iterable<org.h2.mvstore.SFChunk> chunks)

Description copied from class: FileStore

Mark the space occupied by specified chunks as free.

Specified by:

freeChunkSpace in class FileStore<org.h2.mvstore.SFChunk>

Parameters:

chunks - chunks to be processed

free

protected void free(long pos,
                    int length)

Mark the space as free.

Parameters:

pos - the position in bytes

length - the number of bytes

getFillRate

public int getFillRate()

Specified by:

getFillRate in class FileStore<org.h2.mvstore.SFChunk>

validateFileLength

protected final boolean validateFileLength(java.lang.String msg)

Specified by:

validateFileLength in class FileStore<org.h2.mvstore.SFChunk>

readStoreHeader

protected void readStoreHeader(boolean recoveryMode)

Specified by:

readStoreHeader in class FileStore<org.h2.mvstore.SFChunk>

initializeStoreHeader

protected void initializeStoreHeader(long time)

Specified by:

initializeStoreHeader in class FileStore<org.h2.mvstore.SFChunk>

allocateChunkSpace

protected final void allocateChunkSpace(org.h2.mvstore.SFChunk chunk,
                                        WriteBuffer buff)

Description copied from class: FileStore

Allocate logical space and assign position of the buffer within the store.

Specified by:

allocateChunkSpace in class FileStore<org.h2.mvstore.SFChunk>

Parameters:

chunk - to allocate space for

buff - to allocate space for

writeChunk

protected final void writeChunk(org.h2.mvstore.SFChunk chunk,
                                WriteBuffer buffer)

Description copied from class: FileStore

Write buffer associated with chunk into store at chunk's allocated position

Specified by:

writeChunk in class FileStore<org.h2.mvstore.SFChunk>

Parameters:

chunk - chunk to write

buffer - to write

writeCleanShutdownMark

protected final void writeCleanShutdownMark()

Description copied from class: FileStore

Performs final preparation before store is closed normally

Specified by:

writeCleanShutdownMark in class FileStore<org.h2.mvstore.SFChunk>

adjustStoreToLastChunk

protected final void adjustStoreToLastChunk()

Description copied from class: FileStore

Make persistent changes after lastChunk was reset

Specified by:

adjustStoreToLastChunk in class FileStore<org.h2.mvstore.SFChunk>

compactStore

protected void compactStore(int thresholdFillRate,
                            long maxCompactTime,
                            int maxWriteSize,
                            MVStore mvStore)

Compact store file, that is, compact blocks that have a low fill rate, and move chunks next to each other. This will typically shrink the file. Changes are flushed to the file, and old chunks are overwritten.

Specified by:

compactStore in class FileStore<org.h2.mvstore.SFChunk>

Parameters:

thresholdFillRate - do not compact if store fill rate above this value (0-100)

maxCompactTime - the maximum time in milliseconds to compact

maxWriteSize - the maximum amount of data to be written as part of this call

mvStore - that owns this FileStore

compactMoveChunks

public void compactMoveChunks(int targetFillRate,
                              long moveSize,
                              MVStore mvStore)

Compact the store by moving all chunks next to each other, if there is free space between chunks. This might temporarily increase the file size. Chunks are overwritten irrespective of the current retention time. Before overwriting chunks and before resizing the file, syncFile() is called.

Parameters:

targetFillRate - do nothing if the file store fill rate is higher than this

moveSize - the number of bytes to move

mvStore - owner of this store

shrinkStoreIfPossible

protected void shrinkStoreIfPossible(int minPercent)

Shrink the store if possible, and if at least a given percentage can be saved.

Specified by:

shrinkStoreIfPossible in class FileStore<org.h2.mvstore.SFChunk>

Parameters:

minPercent - the minimum percentage to save

doHousekeeping

protected void doHousekeeping(MVStore mvStore)
                       throws java.lang.InterruptedException

Specified by:

doHousekeeping in class FileStore<org.h2.mvstore.SFChunk>

Throws:

java.lang.InterruptedException

truncate

protected abstract void truncate(long size)

clear

public void clear()

Mark the file as empty.

Overrides:

clear in class FileStore<org.h2.mvstore.SFChunk>

getMovePriority

public int getMovePriority(int block)

Calculates relative "priority" for chunk to be moved.

Parameters:

block - where chunk starts

Returns:

priority, bigger number indicate that chunk need to be moved sooner

getAfterLastBlock_

protected long getAfterLastBlock_()

getRewriteCandidates

public java.util.Collection<org.h2.mvstore.SFChunk> getRewriteCandidates()

Overrides:

getRewriteCandidates in class FileStore<org.h2.mvstore.SFChunk>