com.google.cloud.spanner

Interface TransactionManager

All Superinterfaces:

AutoCloseable

public interface TransactionManager
extends AutoCloseable

An interface for managing the life cycle of a read write transaction including all its retries. See TransactionContext for a description of transaction semantics.

At any point in time there can be at most one active transaction in this manager. When that transaction is committed, if it fails with an ABORTED error, calling resetForRetry() would create a new TransactionContext. The newly created transaction would use the same session thus increasing its lock priority. If the transaction is committed successfully, or is rolled back or commit fails with any error other than ABORTED, the manager is considered complete and no further transactions are allowed to be created in it.

Every TransactionManager should either be committed or rolled back. Failure to do so can cause resources to be leaked and deadlocks. Easiest way to guarantee this is by calling close() in a finally block.

See Also:

DatabaseClient.transactionManager()

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	TransactionManager.TransactionState State of the transaction manager.

Method Summary

Modifier and Type	Method and Description
TransactionContext	begin() Creates a new read write transaction.
void	close() Closes the manager.
void	commit() Commits the currently active transaction.
Timestamp	getCommitTimestamp() Returns the commit timestamp if the transaction committed successfully otherwise it will throw IllegalStateException.
TransactionManager.TransactionState	getState() Returns the state of the transaction.
TransactionContext	resetForRetry() Creates a new transaction for retry.
void	rollback() Rolls back the currently active transaction.

Method Detail

begin

TransactionContext begin()

Creates a new read write transaction. This must be called before doing any other operation and can only be called once. To create a new transaction for subsequent retries, see resetForRetry().

commit

void commit()

Commits the currently active transaction. If the transaction was already aborted, then this would throw an AbortedException.

rollback

void rollback()

Rolls back the currently active transaction. In most cases there should be no need to call this explicitly since close() would automatically roll back any active transaction.

resetForRetry

TransactionContext resetForRetry()

Creates a new transaction for retry. This should only be called if the previous transaction failed with ABORTED. In all other cases, this will throw an IllegalStateException. Users should backoff before calling this method. Backoff delay is specified by SpannerException.getRetryDelayInMillis() on the SpannerException throw by the previous commit call.

getCommitTimestamp

Timestamp getCommitTimestamp()

Returns the commit timestamp if the transaction committed successfully otherwise it will throw IllegalStateException.

getState

TransactionManager.TransactionState getState()

Returns the state of the transaction.

close

void close()

Closes the manager. If there is an active transaction, it will be rolled back. Underlying session will be released back to the session pool.

Specified by:

close in interface AutoCloseable