Transaction handles are not free-threaded; transactions handles may be used by multiple threads, but only serially, that is, the application must serialize access to the handle. Once the {@link com.sleepycat.db.Transaction#abort Transaction.abort}, {@link com.sleepycat.db.Transaction#commit Transaction.commit} or {@link com.sleepycat.db.Transaction#discard Transaction.discard} methods are called, the handle may not be accessed again (except to retrieve the commit token), regardless of the success or failure of the method. In addition, parent transactions may not issue any Berkeley DB operations while they have active child transactions (child transactions that have not yet been committed or aborted) except for {@link com.sleepycat.db.Environment#beginTransaction Environment.beginTransaction}, {@link com.sleepycat.db.Transaction#abort Transaction.abort} and {@link com.sleepycat.db.Transaction#commit Transaction.commit}.
To obtain a transaction with default attributes:
Transaction txn = myEnvironment.beginTransaction(null, null);
TransactionConfig config = new TransactionConfig();
config.setDirtyRead(true);
Transaction txn = myEnvironment.beginTransaction(null, config);
This operation can only be performed after this transaction has committed. @return The commit token generated at the commit time of this transaction.
@throws DatabaseException if a failure occurs */ public byte[] getCommitToken() throws IllegalStateException { /* * If iscommitted is true, but txn.commitToken is null, then it's one * of below cases: * 1) either this transaction is a nested txn; or * 2) this environment didn't enable logging; or * 3) the user calls this function on a rep client node. */ if (isCommitted && txn.commitToken == null) { throw new IllegalArgumentException(); } if (isCommitted && txn.commitToken.length == DbConstants.DB_TXN_TOKEN_SIZE) { return txn.commitToken; } throw new IllegalStateException(); } /** Cause an abnormal termination of the transaction.
The log is played backward, and any necessary undo operations are done. Before Transaction.abort returns, any locks held by the transaction will have been released.
In the case of nested transactions, aborting a parent transaction causes all children (unresolved or not) of the parent transaction to be aborted.
All cursors opened within the transaction must be closed before the transaction is aborted. This method closes all open {@link com.sleepycat.db.Cursor Cursor} handles. And if a close operation fails, the rest of the cursors are closed, and the database environment is set to the panic state.
After Transaction.abort has been called, regardless of its return, the {@link com.sleepycat.db.Transaction Transaction} handle may not be accessed again.
@throws DatabaseException if a failure occurs. */ public void abort() throws DatabaseException { txn.abort(); } /** End the transaction. If the environment is configured for synchronous commit, the transaction will be committed synchronously to stable storage before the call returns. This means the transaction will exhibit all of the ACID (atomicity, consistency, isolation, and durability) properties.
If the environment is not configured for synchronous commit, the commit will not necessarily have been committed to stable storage before the call returns. This means the transaction will exhibit the ACI (atomicity, consistency, and isolation) properties, but not D (durability); that is, database integrity will be maintained, but it is possible this transaction may be undone during recovery.
In the case of nested transactions, if the transaction is a parent transaction, committing the parent transaction causes all unresolved children of the parent to be committed. In the case of nested transactions, if the transaction is a child transaction, its locks are not released, but are acquired by its parent. Although the commit of the child transaction will succeed, the actual resolution of the child transaction is postponed until the parent transaction is committed or aborted; that is, if its parent transaction commits, it will be committed; and if its parent transaction aborts, it will be aborted.
All cursors opened within the transaction must be closed before the transaction is committed. If there are {@link com.sleepycat.db.Cursor Cursor} handles open when this method is called, they are all closed inside this method. And if there are errors when closing the cursor handles, the transaction is aborted and the first such error is returned.
After this method returns, the {@link com.sleepycat.db.Transaction Transaction} handle may not be accessed again (except to retrieve the commit token), regardless of the method's success or failure. If the method encounters an error, the transaction and all child transactions of the transaction will have been aborted when the call returns.
@throws DatabaseException if a failure occurs. */ public void commit() throws DatabaseException { txn.commit(0); isCommitted = true; } /** End the transaction, committing synchronously. This means the transaction will exhibit all of the ACID (atomicity, consistency, isolation, and durability) properties.
This behavior is the default for database environments unless otherwise configured using the {@link com.sleepycat.db.EnvironmentConfig#setTxnNoSync EnvironmentConfig.setTxnNoSync} method. This behavior may also be set for a single transaction using the {@link com.sleepycat.db.Environment#beginTransaction Environment.beginTransaction} method. Any value specified to this method overrides both of those settings.
In the case of nested transactions, if the transaction is a parent transaction, committing the parent transaction causes all unresolved children of the parent to be committed. In the case of nested transactions, if the transaction is a child transaction, its locks are not released, but are acquired by its parent. Although the commit of the child transaction will succeed, the actual resolution of the child transaction is postponed until the parent transaction is committed or aborted; that is, if its parent transaction commits, it will be committed; and if its parent transaction aborts, it will be aborted.
All cursors opened within the transaction must be closed before the transaction is committed. If there are {@link com.sleepycat.db.Cursor Cursor} handles open when this method is called, they are all closed inside this method. And if there are errors when closing the cursor handles, the transaction is aborted and the first such error is returned.
After this method returns, the {@link com.sleepycat.db.Transaction Transaction} handle may not be accessed again (except to retrieve the commit token), regardless of the method's success or failure. If the method encounters an error, the transaction and all child transactions of the transaction will have been aborted when the call returns.
@throws DatabaseException if a failure occurs. */ public void commitSync() throws DatabaseException { txn.commit(DbConstants.DB_TXN_SYNC); isCommitted = true; } /** End the transaction, not committing synchronously. This means the transaction will exhibit the ACI (atomicity, consistency, and isolation) properties, but not D (durability); that is, database integrity will be maintained, but it is possible this transaction may be undone during recovery.
This behavior may be set for a database environment using the {@link com.sleepycat.db.EnvironmentConfig#setTxnNoSync EnvironmentConfig.setTxnNoSync} method or for a single transaction using the {@link com.sleepycat.db.Environment#beginTransaction Environment.beginTransaction} method. Any value specified to this method overrides both of those settings.
In the case of nested transactions, if the transaction is a parent transaction, committing the parent transaction causes all unresolved children of the parent to be committed. In the case of nested transactions, if the transaction is a child transaction, its locks are not released, but are acquired by its parent. Although the commit of the child transaction will succeed, the actual resolution of the child transaction is postponed until the parent transaction is committed or aborted; that is, if its parent transaction commits, it will be committed; and if its parent transaction aborts, it will be aborted.
All cursors opened within the transaction must be closed before the transaction is committed. If there are {@link com.sleepycat.db.Cursor Cursor} handles open when this method is called, they are all closed inside this method. And if there are errors when closing the cursor handles, the transaction is aborted and the first such error is returned.
After this method returns, the {@link com.sleepycat.db.Transaction Transaction} handle may not be accessed again (except to retrieve the commit token), regardless of the method's success or failure. If the method encounters an error, the transaction and all child transactions of the transaction will have been aborted when the call returns.
@throws DatabaseException if a failure occurs. */ public void commitNoSync() throws DatabaseException { txn.commit(DbConstants.DB_TXN_NOSYNC); isCommitted = true; } /** End the transaction, writing but not flushing the log. This means the transaction will exhibit the ACI (atomicity, consistency, and isolation) properties, but not D (durability); that is, database integrity will be maintained, but it is possible this transaction may be undone during recovery in the event that the operating system crashes. This option provides more durability than an asynchronous commit and has less performance cost than a synchronous commit.
This behavior may be set for a database environment using the {@link com.sleepycat.db.EnvironmentConfig#setTxnWriteNoSync EnvironmentConfig.setTxnWriteNoSync} method or for a single transaction using the {@link com.sleepycat.db.Environment#beginTransaction Environment.beginTransaction} method. Any value specified to this method overrides both of those settings.
In the case of nested transactions, if the transaction is a parent transaction, committing the parent transaction causes all unresolved children of the parent to be committed. In the case of nested transactions, if the transaction is a child transaction, its locks are not released, but are acquired by its parent. Although the commit of the child transaction will succeed, the actual resolution of the child transaction is postponed until the parent transaction is committed or aborted; that is, if its parent transaction commits, it will be committed; and if its parent transaction aborts, it will be aborted.
All cursors opened within the transaction must be closed before the transaction is committed. If there are {@link com.sleepycat.db.Cursor Cursor} handles open when this method is called, they are all closed inside this method. And if there are errors when closing the cursor handles, the transaction is aborted and the first such error is returned.
After this method returns, the {@link com.sleepycat.db.Transaction Transaction} handle may not be accessed again (except to retrieve the commit token), regardless of the method's success or failure. If the method encounters an error, the transaction and all child transactions of the transaction will have been aborted when the call returns.
@throws DatabaseException if a failure occurs. */ public void commitWriteNoSync() throws DatabaseException { txn.commit(DbConstants.DB_TXN_WRITE_NOSYNC); isCommitted = true; } /** Free up all the per-process resources associated with the specified {@link com.sleepycat.db.Transaction Transaction} handle, neither committing nor aborting the transaction. This call may be used only after calls to {@link com.sleepycat.db.Environment#recover Environment.recover} when there are multiple global transaction managers recovering transactions in a single database environment. Any transactions returned by {@link com.sleepycat.db.Environment#recover Environment.recover} that are not handled by the current global transaction manager should be discarded using this method. If there are {@link com.sleepycat.db.Cursor Cursor} handles open when this method is called, they are all closed inside this method. And if there are errors when closing the cursor handles, the first such error is returned.
The {@link com.sleepycat.db.Transaction Transaction} handle may not be accessed again after this method has been called, regardless of the method's success or failure.
@throws DatabaseException if a failure occurs. */ public void discard() throws DatabaseException { txn.discard(0); } /** Return the transaction's unique ID.
Locking calls made on behalf of this transaction should use the value returned from this method as the locker parameter to the {@link com.sleepycat.db.Environment#getLock Environment.getLock} or {@link com.sleepycat.db.Environment#lockVector Environment.lockVector} calls.
@return The transaction's unique ID.
@throws DatabaseException if a failure occurs. */ public int getId() throws DatabaseException { return txn.id(); } /** Get the user visible name for the transaction.
@return The user visible name for the transaction.
*/ public String getName() throws DatabaseException { return txn.get_name(); } /** Get the transaction's deadlock priority.
@return The deadlock priority for the transaction.
@throws DatabaseException if a failure occurs */ public int getPriority() throws DatabaseException { return txn.get_priority(); } /** Initiate the beginning of a two-phase commit.
In a distributed transaction environment, Berkeley DB can be used as a local transaction manager. In this case, the distributed transaction manager must send prepare messages to each local manager. The local manager must then issue a {@link com.sleepycat.db.Transaction#prepare Transaction.prepare} call and await its successful return before responding to the distributed transaction manager. Only after the distributed transaction manager receives successful responses from all of its prepare messages should it issue any commit messages.
In the case of nested transactions, preparing the parent causes all unresolved children of the parent transaction to be committed. Child transactions should never be explicitly prepared. Their fate will be resolved along with their parent's during global recovery.
If there are {@link com.sleepycat.db.Cursor Cursor} handles open when this method is called, they are all closed inside this method. And if there are errors when closing the cursor handles, the first such error is returned.
@param gid The global transaction ID by which this transaction will be known. This global transaction ID will be returned in calls to {@link com.sleepycat.db.Environment#recover Environment.recover} method, telling the application which global transactions must be resolved. The gid parameter must be sized at least DB_XIDDATASIZE (currently 128) bytes; only the first DB_XIDDATASIZE bytes are used.
@throws DatabaseException if a failure occurs. */ public void prepare(final byte[] gid) throws DatabaseException { txn.prepare(gid); } /** Set the user visible name for the transaction.
@param name The user visible name for the transaction.
*/ public void setName(final String name) throws DatabaseException { txn.set_name(name); } /** Set the deadlock priority for this transaction. The deadlock detector will reject lock requests from lower priority transactions before those from higher priority transactions.
@param priority The deadlock priority for the transaction.
@throws DatabaseException if a failure occurs. */ public void setPriority(int priority) throws DatabaseException { txn.set_priority(priority); } /** Configure the timeout value for the transaction lifetime.
If the transaction runs longer than this time, the transaction may may throw {@link com.sleepycat.db.DatabaseException DatabaseException}.
Timeouts are checked whenever a thread of control blocks on a lock or when deadlock detection is performed. For this reason, the accuracy of the timeout depends on how often deadlock detection is performed.
@param timeOut The timeout value for the transaction lifetime, in microseconds. As the value is an unsigned 32-bit number of microseconds, the maximum timeout is roughly 71 minutes. A value of 0 disables timeouts for the transaction.
This method may be called at any time during the life of the application.
@throws DatabaseException if a failure occurs. */ public void setTxnTimeout(final long timeOut) throws DatabaseException { txn.set_timeout(timeOut, DbConstants.DB_SET_TXN_TIMEOUT); } /** Configure the lock request timeout value for the transaction.
If a lock request cannot be granted in this time, the transaction may throw {@link com.sleepycat.db.DatabaseException DatabaseException}.
Timeouts are checked whenever a thread of control blocks on a lock or when deadlock detection is performed. For this reason, the accuracy of the timeout depends on how often deadlock detection is performed.
@param timeOut The lock request timeout value for the transaction, in microseconds. As the value is an unsigned 32-bit number of microseconds, the maximum timeout is roughly 71 minutes. A value of 0 disables timeouts for the transaction.
This method may be called at any time during the life of the application.
@throws DatabaseException if a failure occurs. */ public void setLockTimeout(final long timeOut) throws DatabaseException { txn.set_timeout(timeOut, DbConstants.DB_SET_LOCK_TIMEOUT); } }