co.cask.tephra

Interface TransactionSystemClient

All Known Implementing Classes:

DetachedTxSystemClient, InMemoryTxSystemClient, MinimalTxSystemClient, TransactionServiceClient

public interface TransactionSystemClient

Client talking to transaction system. See also TransactionAware. todo: explain Omid.

Method Summary

Methods

Modifier and Type	Method and Description
void	abort(Transaction tx) Makes transaction visible.
boolean	canCommit(Transaction tx, Collection<byte[]> changeIds) Checks if transaction with the set of changes can be committed.
Transaction	checkpoint(Transaction tx) Performs a checkpoint operation on the current transaction, returning a new Transaction instance with the updated state.
boolean	commit(Transaction tx) Makes transaction visible.
int	getInvalidSize()
InputStream	getSnapshotInputStream() Retrieves the state of the transaction manager and send it as a stream.
boolean	invalidate(long tx) Makes transaction invalid.
void	resetState() Resets the state of the transaction manager.
Transaction	startLong() Starts new long transaction.
Transaction	startShort() Starts new short transaction.
Transaction	startShort(int timeout) Starts new short transaction.
String	status() Return the status of the transaction Manager
boolean	truncateInvalidTx(Set<Long> invalidTxIds) Removes the given transaction ids from the invalid list.
boolean	truncateInvalidTxBefore(long time) Removes all transaction ids started before the given time from invalid list.

Method Detail

startShort

Transaction startShort()

Starts new short transaction.

Returns:

instance of Transaction

startShort

Transaction startShort(int timeout)

Starts new short transaction.

Parameters:

timeout - the timeout for the transaction

Returns:

instance of Transaction

startLong

Transaction startLong()

Starts new long transaction.

Returns:

instance of Transaction

canCommit

boolean canCommit(Transaction tx,
                Collection<byte[]> changeIds)
                  throws TransactionNotInProgressException

Checks if transaction with the set of changes can be committed. E.g. it can check conflicts with other changes and refuse commit if there are conflicts. It is assumed that no other changes will be done in between this method call and commit(Transaction) which may check conflicts again to avoid races.

Since we do conflict detection at commit time as well, this may seem redundant. The idea is to check for conflicts before we persist changes to avoid rollback in case of conflicts as much as possible. NOTE: in some situations we may want to skip this step to save on RPC with a risk of many rollback ops. So by default we take safe path.

Parameters:

tx - transaction to verify

changeIds - ids of changes made by transaction

Returns:

true if transaction can be committed otherwise false

Throws:

TransactionNotInProgressException

commit

boolean commit(Transaction tx)
               throws TransactionNotInProgressException

Makes transaction visible. It will again check conflicts of changes submitted previously with canCommit(Transaction, java.util.Collection)

Parameters:

tx - transaction to make visible.

Returns:

true if transaction can be committed otherwise false

Throws:

TransactionNotInProgressException

abort

void abort(Transaction tx)

Makes transaction visible. You should call it only when all changes of this tx are undone. NOTE: it will not throw TransactionNotInProgressException if transaction has timed out.

Parameters:

tx - transaction to make visible.

invalidate

boolean invalidate(long tx)

Makes transaction invalid. You should call it if not all changes of this tx could be undone. NOTE: it will not throw TransactionNotInProgressException if transaction has timed out.

Parameters:

tx - transaction id to invalidate.

Returns:

true if transaction has been successfully invalidated

checkpoint

Transaction checkpoint(Transaction tx)
                       throws TransactionNotInProgressException

Performs a checkpoint operation on the current transaction, returning a new Transaction instance with the updated state. A checkpoint operation assigns a new write pointer for the current transaction.

Parameters:

tx - the current transaction to checkpoint

Returns:

an updated transaction instance with the new write pointer

Throws:

TransactionNotInProgressException

getSnapshotInputStream

InputStream getSnapshotInputStream()
                                   throws TransactionCouldNotTakeSnapshotException

Retrieves the state of the transaction manager and send it as a stream. The snapshot will not be persisted.

Returns:

an input stream containing an encoded snapshot of the transaction manager

Throws:

TransactionCouldNotTakeSnapshotException

status

String status()

Return the status of the transaction Manager

Returns:

a String which denotes the status of txManager

resetState

void resetState()

Resets the state of the transaction manager.

truncateInvalidTx

boolean truncateInvalidTx(Set<Long> invalidTxIds)

Removes the given transaction ids from the invalid list.

Parameters:

invalidTxIds - transaction ids

Returns:

true if invalid list got changed, false otherwise

truncateInvalidTxBefore

boolean truncateInvalidTxBefore(long time)
                                throws InvalidTruncateTimeException

Removes all transaction ids started before the given time from invalid list.

Parameters:

time - time in milliseconds

Returns:

true if invalid list got changed, false otherwise

Throws:

InvalidTruncateTimeException - if there are any in-progress transactions started before given time

getInvalidSize

int getInvalidSize()

Returns:

the size of invalid list