TransactionStore

A store that supports concurrent MVCC read-committed transactions.

Methods
static long	getLogId(long operationId) Get the log id for the given operation id.
static long	getLogId(long operationId) Get the log id for the given operation id. Parameters: operationId - the operation id Returns: the log id
static long	getOperationId(int transactionId, long logId) Combine the transaction id and the log id to an operation id.
static long	getOperationId(int transactionId, long logId) Combine the transaction id and the log id to an operation id. Parameters: transactionId - the transaction id logId - the log id Returns: the operation id
static int	getTransactionId(long operationId) Get the transaction id for the given operation id.
static int	getTransactionId(long operationId) Get the transaction id for the given operation id. Parameters: operationId - the operation id Returns: the transaction id
	TransactionStore(MVStore store) Create a new transaction store.
	TransactionStore(MVStore store) Create a new transaction store. Parameters: store - the store
	TransactionStore(MVStore store, DataType dataType) Create a new transaction store.
	TransactionStore(MVStore store, DataType dataType) Create a new transaction store. Parameters: store - the store dataType - the data type for map keys and values
TransactionStore.Transaction	begin() Begin a new transaction.
TransactionStore.Transaction	begin() Begin a new transaction. Returns: the transaction
void	close() Close the transaction store.
void	close() Close the transaction store.
void	commit(TransactionStore.Transaction t, long maxLogId) Commit a transaction.
void	commit(TransactionStore.Transaction t, long maxLogId) Commit a transaction. Parameters: t - the transaction maxLogId - the last log id
MVMap	createTempMap() Create a temporary map.
MVMap	createTempMap() Create a temporary map. Such maps are removed when opening the store. Returns: the map
void	endTransaction(TransactionStore.Transaction t, int oldStatus) End this transaction
void	endTransaction(TransactionStore.Transaction t, int oldStatus) End this transaction Parameters: t - the transaction oldStatus - status of this transaction
Iterator	getChanges(TransactionStore.Transaction t, long maxLogId, long toLogId) Get the changes of the given transaction, starting from the latest log id back to the given log id.
Iterator	getChanges(TransactionStore.Transaction t, long maxLogId, long toLogId) Get the changes of the given transaction, starting from the latest log id back to the given log id. Parameters: t - the transaction maxLogId - the maximum log id toLogId - the minimum log id Returns: the changes
List	getOpenTransactions() Get the list of unclosed transactions that have pending writes.
List	getOpenTransactions() Get the list of unclosed transactions that have pending writes. Returns: the list of transactions (sorted by id)
void	init() Initialize the store.
void	init() Initialize the store. This is needed before a transaction can be opened. If the transaction store is corrupt, this method can throw an exception, in which case the store can only be used for reading.
void	log(TransactionStore.Transaction t, long logId, int mapId, Object key, Object oldValue) Log an entry.
void	log(TransactionStore.Transaction t, long logId, int mapId, Object key, Object oldValue) Log an entry. Parameters: t - the transaction logId - the log id mapId - the map id key - the key oldValue - the old value
void	logUndo(TransactionStore.Transaction t, long logId) Remove a log entry.
void	logUndo(TransactionStore.Transaction t, long logId) Remove a log entry. Parameters: t - the transaction logId - the log id
MVMap	openMap(String name, DataType keyType, DataType valueType) Open the map with the given name.
MVMap	openMap(String name, DataType keyType, DataType valueType) Open the map with the given name. Parameters: name - the map name keyType - the key type valueType - the value type Returns: the map
MVMap	openMap(int mapId) Open the map with the given id.
MVMap	openMap(int mapId) Open the map with the given id. Parameters: mapId - the id Returns: the map
MVMap	openTempMap(String mapName) Open a temporary map.
MVMap	openTempMap(String mapName) Open a temporary map. Parameters: mapName - the map name Returns: the map
void	removeMap(TransactionStore.TransactionMap map) Remove the given map.
void	removeMap(TransactionStore.TransactionMap map) Remove the given map. Parameters: map - the map
void	rollbackTo(TransactionStore.Transaction t, long maxLogId, long toLogId) Rollback to an old savepoint.
void	rollbackTo(TransactionStore.Transaction t, long maxLogId, long toLogId) Rollback to an old savepoint. Parameters: t - the transaction maxLogId - the last log id toLogId - the log id to roll back to
void	setMaxTransactionId(int max) Set the maximum transaction id, after which ids are re-used.
void	setMaxTransactionId(int max) Set the maximum transaction id, after which ids are re-used. If the old transaction is still in use when re-using an old id, the new transaction fails. Parameters: max - the maximum id
void	storeTransaction(TransactionStore.Transaction t) Store a transaction.
void	storeTransaction(TransactionStore.Transaction t) Store a transaction. Parameters: t - the transaction

Fields
static MVMap	preparedTransactions
static ReentrantReadWriteLock	rwLock
static MVStore	store
static MVMap	undoLog

preparedTransactions

The persisted map of prepared transactions. Key: transactionId, value: [ status, name ].

rwLock

the reader/writer lock for the undo-log. Allows us to process multiple selects in parallel.

store

The store.

undoLog

The undo log.

If the first entry for a transaction doesn't have a logId of 0, then the transaction is partially committed (which means rollback is not possible). Log entries are written before the data is changed (write-ahead).

Key: opId, value: [ mapId, key, oldValue ].