com.caucho.db.store
Class Store

java.lang.Object
  com.caucho.db.store.Store

Direct Known Subclasses:

Table

public class Store
extends java.lang.Object

The store manages the block-based persistent store file. Each table will have its own store file, table.db. The store is block-based, where each block is 64k. Block allocation is tracked by a free block, block 0. Each block is represented as a two-byte value. The first byte is the allocation code: free, row, or used. The second byte is a fragment allocation mask. Since 64k stores 32k entries, the allocation block can handle a 2G database size. If the database is larger, another free block occurs at block 32k handling another 2G. The blocks are marked as free (00), row (01), used (10) or fragment(11). Row-blocks are table rows, so a table iterator will only look at the row blocks. Used blocks are for special blocks like the free list. Fragments are for blobs. Each store has a unique id in the database. The store id is merged with the block number in the store to create a unique block id. There are 64k allowed stores (and therefore 64k tables), leaving 64 - 16 = 48 bits for the blocks in a table, i.e. 2 ^ 48 blocks = 256T blocks. block index: the block number in the file. address: the address of a byte within the store, treating the file as a flat file. block id: the unique id of the block in the database.

Blobs and fragments

Fragments are stored in 8k chunks with a single byte prefix indicating its use.

Transactions

Fragments are not associated with transactions. The rollback is associated with a transaction.

Field Summary

protected BlockManager	_blockManager
protected Database	_database
static int	ALLOC_FRAGMENT
static int	ALLOC_FREE
static int	ALLOC_INDEX
static int	ALLOC_MASK
static int	ALLOC_MINI_FRAG
static int	ALLOC_ROW
static int	ALLOC_USED
static int	BLOCK_BITS
static long	BLOCK_INDEX_MASK
static long	BLOCK_MASK
static long	BLOCK_OFFSET_MASK
static int	BLOCK_SIZE
static long	DATA_START
static int	FRAGMENT_PER_BLOCK
static int	FRAGMENT_SIZE
static int	MINI_FRAG_ALLOC_OFFSET
static int	MINI_FRAG_PER_BLOCK
static int	MINI_FRAG_SIZE
static int	STORE_CREATE_END

Constructor Summary

Store(Database database, java.lang.String name, Lock tableLock)

Store(Database database, java.lang.String name, Lock rowLock, Path path)
Creates a new store.

Method Summary

long	addressToBlockId(long address) Converts from the block index to the unique block id.
Block	allocateBlock() Allocates a new block for a non-row.
long	allocateFragment(StoreTransaction xa) Allocates a new fragment.
Block	allocateIndexBlock() Allocates a new block for an index
long	allocateMiniFragment(StoreTransaction xa) Allocates a new miniFragment.
Block	allocateRow() Allocates a new block for a row.
protected void	assertStoreActive() Check that an allocated block is valid.
static long	blockIdToAddress(long blockId) Converts from the block index to the unique block id.
static long	blockIdToAddress(long blockId, int offset) Converts from the block index to the unique block id.
void	close() Closes the store.
static java.lang.String	codeToName(int code) Debug names for the allocation.
void	create() Creates the store.
static Store	create(Path path) Creates an independent store.
void	deleteFragment(StoreTransaction xa, long fragmentAddress) Deletes a fragment.
void	deleteMiniFragment(StoreTransaction xa, long fragmentAddress) Deletes a miniFragment.
long	firstBlock(long blockId, int type) Returns the first block id which contains a row.
long	firstFragment(long blockId) Returns the first block id which contains a fragment.
long	firstRow(long blockId) Returns the first block id which contains a row.
void	flush() Flush the store.
protected void	freeBlock(long blockId) Frees a block.
byte[]	getAllocationTable() Returns a copy of the allocation table.
long	getBlockCount() Returns the block count.
BlockManager	getBlockManager() Returns the block manager.
long	getFileSize() Returns the file size.
int	getId() Returns the store's id.
Lock	getLock() Returns the table's lock.
java.lang.String	getName() Returns the store's name.
long	getTotalFragmentSize() Returns the current number of fragments used.
void	init()
boolean	isClosed() True if destroyed.
boolean	isCorrupted()
boolean	isFlushDirtyBlocksOnCommit() If true, dirty blocks are written at commit time.
boolean	isIndexBlock(long blockAddress) Return true if the block is an index block.
boolean	isRowBlock(long blockAddress) Return true if the block is a row block.
Block	readBlock(long blockAddress) Returns the matching block.
void	readBlock(long blockId, byte[] buffer, int offset, int length) Reads a block into the buffer.
int	readBlock(long blockAddress, int blockOffset, byte[] buffer, int offset, int length) Reads a block.
int	readBlock(long blockAddress, int blockOffset, char[] buffer, int offset, int length) Reads a block for a clob.
long	readBlockLong(long blockAddress, int offset) Reads a long value from a block.
int	readFragment(long fragmentAddress, int fragmentOffset, byte[] buffer, int offset, int length) Reads a fragment.
int	readFragment(long fragmentAddress, int fragmentOffset, char[] buffer, int offset, int length) Reads a fragment for a clob.
long	readFragmentLong(long fragmentAddress, int fragmentOffset) Reads a long value from a fragment.
static long	readLong(byte[] buffer, int offset) Reads the long.
int	readMiniFragment(long fragmentAddress, int fragmentOffset, byte[] buffer, int offset, int length) Reads a fragment.
int	readMiniFragment(long fragmentAddress, int fragmentOffset, char[] buffer, int offset, int length) Reads a miniFragment for a clob.
long	readMiniFragmentLong(long fragmentAddress, int fragmentOffset) Reads a long value from a miniFragment.
void	remove()
void	setCorrupted(boolean isCorrupted)
void	setFlushDirtyBlocksOnCommit(boolean flushOnCommit) If true, dirty blocks are written at commit time.
java.lang.String	toString()
protected void	validateBlockId(long blockId) Check that an allocated block is valid.
void	writeBlock(long blockAddress, byte[] buffer, int offset, int length) Saves the buffer to the database.
void	writeBlock(StoreTransaction xa, long blockAddress, int blockOffset, byte[] buffer, int offset, int length) Writes a blockfragment.
void	writeBlock(StoreTransaction xa, long blockAddress, int blockOffset, char[] buffer, int offset, int length) Writes a character based block
void	writeBlockLong(StoreTransaction xa, long blockAddress, int offset, long value) Writes a long value to a block
void	writeFragment(StoreTransaction xa, long fragmentAddress, int fragmentOffset, byte[] buffer, int offset, int length) Writes a fragment.
void	writeFragment(StoreTransaction xa, long fragmentAddress, int fragmentOffset, char[] buffer, int offset, int length) Writes a character based
void	writeFragmentLong(StoreTransaction xa, long fragmentAddress, int fragmentOffset, long value) Writes a long value to a fragment.
static void	writeLong(byte[] buffer, int offset, long v) Writes the long.
void	writeMiniFragment(StoreTransaction xa, long fragmentAddress, int fragmentOffset, byte[] buffer, int offset, int length) Writes a miniFragment.
void	writeMiniFragment(StoreTransaction xa, long fragmentAddress, int fragmentOffset, char[] buffer, int offset, int length) Writes a character based
void	writeMiniFragmentLong(StoreTransaction xa, long fragmentAddress, int fragmentOffset, long value) Writes a long value to a miniFragment.

Methods inherited from class java.lang.Object

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

Field Detail

BLOCK_BITS

public static final int BLOCK_BITS

See Also:

Constant Field Values

BLOCK_SIZE

public static final int BLOCK_SIZE

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Constant Field Values

BLOCK_INDEX_MASK

public static final long BLOCK_INDEX_MASK

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Constant Field Values

BLOCK_MASK

public static final long BLOCK_MASK

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Constant Field Values

BLOCK_OFFSET_MASK

public static final long BLOCK_OFFSET_MASK

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Constant Field Values

ALLOC_FREE

public static final int ALLOC_FREE

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Constant Field Values

ALLOC_ROW

public static final int ALLOC_ROW

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Constant Field Values

ALLOC_USED

public static final int ALLOC_USED

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Constant Field Values

ALLOC_FRAGMENT

public static final int ALLOC_FRAGMENT

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Constant Field Values

ALLOC_INDEX

public static final int ALLOC_INDEX

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Constant Field Values

ALLOC_MINI_FRAG

public static final int ALLOC_MINI_FRAG

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Constant Field Values

ALLOC_MASK

public static final int ALLOC_MASK

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Constant Field Values

FRAGMENT_SIZE

public static final int FRAGMENT_SIZE

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Constant Field Values

FRAGMENT_PER_BLOCK

public static final int FRAGMENT_PER_BLOCK

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Constant Field Values

MINI_FRAG_SIZE

public static final int MINI_FRAG_SIZE

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Constant Field Values

MINI_FRAG_PER_BLOCK

public static final int MINI_FRAG_PER_BLOCK

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Constant Field Values

MINI_FRAG_ALLOC_OFFSET

public static final int MINI_FRAG_ALLOC_OFFSET

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Constant Field Values

DATA_START

public static final long DATA_START

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Constant Field Values

STORE_CREATE_END

public static final int STORE_CREATE_END

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Constant Field Values

_database

protected final Database _database

_blockManager

protected final BlockManager _blockManager

Constructor Detail

Store

public Store(Database database,
             java.lang.String name,
             Lock tableLock)

Store

public Store(Database database,
             java.lang.String name,
             Lock rowLock,
             Path path)

Creates a new store.

Parameters:

database - the owning database.

name - the store name

lock - the table lock

path - the path to the files

Method Detail

create

public static Store create(Path path)
                    throws java.io.IOException,
                           java.sql.SQLException

Creates an independent store.

Throws:

java.io.IOException

java.sql.SQLException

setFlushDirtyBlocksOnCommit

public void setFlushDirtyBlocksOnCommit(boolean flushOnCommit)

If true, dirty blocks are written at commit time.

isFlushDirtyBlocksOnCommit

public boolean isFlushDirtyBlocksOnCommit()

If true, dirty blocks are written at commit time.

getName

public java.lang.String getName()

Returns the store's name.

getId

public int getId()

Returns the store's id.

getLock

public Lock getLock()

Returns the table's lock.

getBlockManager

public BlockManager getBlockManager()

Returns the block manager.

setCorrupted

public void setCorrupted(boolean isCorrupted)

isCorrupted

public boolean isCorrupted()

getFileSize

public long getFileSize()

Returns the file size.

getBlockCount

public long getBlockCount()

Returns the block count.

addressToBlockId

public final long addressToBlockId(long address)

Converts from the block index to the unique block id.

blockIdToAddress

public static long blockIdToAddress(long blockId)

Converts from the block index to the unique block id.

blockIdToAddress

public static long blockIdToAddress(long blockId,
                                    int offset)

Converts from the block index to the unique block id.

getTotalFragmentSize

public long getTotalFragmentSize()

Returns the current number of fragments used.

create

public void create()
            throws java.io.IOException,
                   java.sql.SQLException

Creates the store.

Throws:

java.io.IOException

java.sql.SQLException

init

public void init()
          throws java.io.IOException

Throws:

java.io.IOException

remove

public void remove()
            throws java.sql.SQLException

Throws:

java.sql.SQLException

firstRow

public long firstRow(long blockId)
              throws java.io.IOException

Returns the first block id which contains a row.

Returns:

the block id of the first row block

Throws:

java.io.IOException

firstFragment

public long firstFragment(long blockId)
                   throws java.io.IOException

Returns the first block id which contains a fragment.

Returns:

the block id of the first row block

Throws:

java.io.IOException

firstBlock

public long firstBlock(long blockId,
                       int type)
                throws java.io.IOException

Returns the first block id which contains a row.

Returns:

the block id of the first row block

Throws:

java.io.IOException

readBlock

public final Block readBlock(long blockAddress)
                      throws java.io.IOException

Returns the matching block.

Throws:

java.io.IOException

allocateRow

public Block allocateRow()
                  throws java.io.IOException

Allocates a new block for a row.

Returns:

the block id of the allocated block.

Throws:

java.io.IOException

isRowBlock

public boolean isRowBlock(long blockAddress)

Return true if the block is a row block.

allocateBlock

public Block allocateBlock()
                    throws java.io.IOException

Allocates a new block for a non-row.

Returns:

the block id of the allocated block.

Throws:

java.io.IOException

allocateIndexBlock

public Block allocateIndexBlock()
                         throws java.io.IOException

Allocates a new block for an index

Returns:

the block id of the allocated block.

Throws:

java.io.IOException

isIndexBlock

public boolean isIndexBlock(long blockAddress)

Return true if the block is an index block.

validateBlockId

protected void validateBlockId(long blockId)
                        throws java.lang.IllegalArgumentException,
                               java.lang.IllegalStateException

Check that an allocated block is valid.

Throws:

java.lang.IllegalArgumentException

java.lang.IllegalStateException

assertStoreActive

protected void assertStoreActive()
                          throws java.lang.IllegalStateException

Check that an allocated block is valid.

Throws:

java.lang.IllegalStateException

freeBlock

protected void freeBlock(long blockId)
                  throws java.io.IOException

Frees a block.

Throws:

java.io.IOException

readFragment

public int readFragment(long fragmentAddress,
                        int fragmentOffset,
                        byte[] buffer,
                        int offset,
                        int length)
                 throws java.io.IOException

Reads a fragment.

Parameters:

fragmentAddress - the address of the fragment

fragmentOffset - the offset inside the fragment to start reading

buffer - the result buffer

offset - offset into the result buffer

length - the number of bytes to read

Returns:

the number of bytes read

Throws:

java.io.IOException

readFragment

public int readFragment(long fragmentAddress,
                        int fragmentOffset,
                        char[] buffer,
                        int offset,
                        int length)
                 throws java.io.IOException

Reads a fragment for a clob.

Parameters:

fragmentAddress - the address of the fragment

fragmentOffset - the offset inside the fragment to start reading

buffer - the result buffer

offset - offset into the result buffer

length - the length of the fragment in characters

Returns:

the number of characters read

Throws:

java.io.IOException

readFragmentLong

public long readFragmentLong(long fragmentAddress,
                             int fragmentOffset)
                      throws java.io.IOException

Reads a long value from a fragment.

Returns:

the long value

Throws:

java.io.IOException

readBlock

public int readBlock(long blockAddress,
                     int blockOffset,
                     byte[] buffer,
                     int offset,
                     int length)
              throws java.io.IOException

Reads a block.

Parameters:

blockAddress - the address of the block

blockOffset - the offset inside the block to start reading

buffer - the result buffer

offset - offset into the result buffer

length - the number of bytes to read

Returns:

the number of bytes read

Throws:

java.io.IOException

readBlock

public int readBlock(long blockAddress,
                     int blockOffset,
                     char[] buffer,
                     int offset,
                     int length)
              throws java.io.IOException

Reads a block for a clob.

Parameters:

blockAddress - the address of the block

blockOffset - the offset inside the block to start reading

buffer - the result buffer

offset - offset into the result buffer

length - the length of the block in characters

Returns:

the number of characters read

Throws:

java.io.IOException

readBlockLong

public long readBlockLong(long blockAddress,
                          int offset)
                   throws java.io.IOException

Reads a long value from a block.

Returns:

the long value

Throws:

java.io.IOException

allocateFragment

public long allocateFragment(StoreTransaction xa)
                      throws java.io.IOException

Allocates a new fragment.

Returns:

the fragment address

Throws:

java.io.IOException

deleteFragment

public void deleteFragment(StoreTransaction xa,
                           long fragmentAddress)
                    throws java.io.IOException

Deletes a fragment.

Throws:

java.io.IOException

writeFragment

public void writeFragment(StoreTransaction xa,
                          long fragmentAddress,
                          int fragmentOffset,
                          byte[] buffer,
                          int offset,
                          int length)
                   throws java.io.IOException

Writes a fragment.

Parameters:

xa - the owning transaction

fragmentAddress - the fragment to write

fragmentOffset - the offset into the fragment

buffer - the write buffer

offset - offset into the write buffer

length - the number of bytes to write

Throws:

java.io.IOException

writeFragment

public void writeFragment(StoreTransaction xa,
                          long fragmentAddress,
                          int fragmentOffset,
                          char[] buffer,
                          int offset,
                          int length)
                   throws java.io.IOException

Writes a character based

Parameters:

fragmentAddress - the fragment to write

fragmentOffset - the offset into the fragment

buffer - the write buffer

offset - offset into the write buffer

length - the number of bytes to write

Throws:

java.io.IOException

writeFragmentLong

public void writeFragmentLong(StoreTransaction xa,
                              long fragmentAddress,
                              int fragmentOffset,
                              long value)
                       throws java.io.IOException

Writes a long value to a fragment.

Throws:

java.io.IOException

writeBlock

public void writeBlock(StoreTransaction xa,
                       long blockAddress,
                       int blockOffset,
                       byte[] buffer,
                       int offset,
                       int length)
                throws java.io.IOException

Writes a blockfragment.

Parameters:

xa - the owning transaction

blockAddress - the block to write

blockOffset - the offset into the block

buffer - the write buffer

offset - offset into the write buffer

length - the number of bytes to write

Throws:

java.io.IOException

writeBlock

public void writeBlock(StoreTransaction xa,
                       long blockAddress,
                       int blockOffset,
                       char[] buffer,
                       int offset,
                       int length)
                throws java.io.IOException

Writes a character based block

Parameters:

blockAddress - the fragment to write

blockOffset - the offset into the fragment

buffer - the write buffer

offset - offset into the write buffer

length - the number of bytes to write

Throws:

java.io.IOException

writeBlockLong

public void writeBlockLong(StoreTransaction xa,
                           long blockAddress,
                           int offset,
                           long value)
                    throws java.io.IOException

Writes a long value to a block

Throws:

java.io.IOException

readMiniFragment

public int readMiniFragment(long fragmentAddress,
                            int fragmentOffset,
                            byte[] buffer,
                            int offset,
                            int length)
                     throws java.io.IOException

Reads a fragment.

Parameters:

fragmentAddress - the address of the fragment

fragmentOffset - the offset inside the fragment to start reading

buffer - the result buffer

offset - offset into the result buffer

length - the number of bytes to read

Returns:

the number of bytes read

Throws:

java.io.IOException

readMiniFragment

public int readMiniFragment(long fragmentAddress,
                            int fragmentOffset,
                            char[] buffer,
                            int offset,
                            int length)
                     throws java.io.IOException

Reads a miniFragment for a clob.

Parameters:

fragmentAddress - the address of the fragment

fragmentOffset - the offset inside the fragment to start reading

buffer - the result buffer

offset - offset into the result buffer

length - the length of the fragment in characters

Returns:

the number of characters read

Throws:

java.io.IOException

readMiniFragmentLong

public long readMiniFragmentLong(long fragmentAddress,
                                 int fragmentOffset)
                          throws java.io.IOException

Reads a long value from a miniFragment.

Returns:

the long value

Throws:

java.io.IOException

allocateMiniFragment

public long allocateMiniFragment(StoreTransaction xa)
                          throws java.io.IOException

Allocates a new miniFragment.

Returns:

the fragment address

Throws:

java.io.IOException

deleteMiniFragment

public void deleteMiniFragment(StoreTransaction xa,
                               long fragmentAddress)
                        throws java.io.IOException

Deletes a miniFragment.

Throws:

java.io.IOException

writeMiniFragment

public void writeMiniFragment(StoreTransaction xa,
                              long fragmentAddress,
                              int fragmentOffset,
                              byte[] buffer,
                              int offset,
                              int length)
                       throws java.io.IOException

Writes a miniFragment.

Parameters:

xa - the owning transaction

fragmentAddress - the fragment to write

fragmentOffset - the offset into the fragment

buffer - the write buffer

offset - offset into the write buffer

length - the number of bytes to write

Throws:

java.io.IOException

writeMiniFragment

public void writeMiniFragment(StoreTransaction xa,
                              long fragmentAddress,
                              int fragmentOffset,
                              char[] buffer,
                              int offset,
                              int length)
                       throws java.io.IOException

Writes a character based

Parameters:

miniFragmentAddress - the fragment to write

fragmentOffset - the offset into the fragment

buffer - the write buffer

offset - offset into the write buffer

length - the number of bytes to write

Throws:

java.io.IOException

writeMiniFragmentLong

public void writeMiniFragmentLong(StoreTransaction xa,
                                  long fragmentAddress,
                                  int fragmentOffset,
                                  long value)
                           throws java.io.IOException

Writes a long value to a miniFragment.

Throws:

java.io.IOException

readBlock

public void readBlock(long blockId,
                      byte[] buffer,
                      int offset,
                      int length)
               throws java.io.IOException

Reads a block into the buffer.

Throws:

java.io.IOException

writeBlock

public void writeBlock(long blockAddress,
                       byte[] buffer,
                       int offset,
                       int length)
                throws java.io.IOException

Saves the buffer to the database.

Throws:

java.io.IOException

flush

public void flush()

Flush the store.

isClosed

public boolean isClosed()

True if destroyed.

close

public void close()

Closes the store.

getAllocationTable

public byte[] getAllocationTable()

Returns a copy of the allocation table.

readLong

public static long readLong(byte[] buffer,
                            int offset)

Reads the long.

writeLong

public static void writeLong(byte[] buffer,
                             int offset,
                             long v)

Writes the long.

codeToName

public static java.lang.String codeToName(int code)

Debug names for the allocation.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object