org.apache.derby.impl.store.raw.log

Class CheckpointOperation

java.lang.Object

org.apache.derby.impl.store.raw.log.CheckpointOperation

All Implemented Interfaces:

java.io.Externalizable, java.io.Serializable, Formatable, TypedFormat, Loggable

public class CheckpointOperation
extends java.lang.Object
implements Loggable

A Log Operation that represents a checkpoint.

See Also:

Loggable, Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected long	redoLWM
protected Formatable	transactionTable
protected long	undoLWM

Fields inherited from interface org.apache.derby.iapi.store.raw.Loggable

ABORT, BI_LOG, CHECKSUM, COMMIT, COMPENSATION, FILE_RESOURCE, FIRST, LAST, PREPARE, RAWSTORE, XA_NEEDLOCK

Constructor Summary

Constructors

Constructor and Description
CheckpointOperation()
CheckpointOperation(long redoLWM, long undoLWM, Formatable ttab)

Method Summary

Methods

Modifier and Type	Method and Description
void	doMe(Transaction xact, LogInstant instant, LimitObjectInput in) Nothing to do unless we are rollforward recovery; Redoing of checkpoints during rollforward recovery allows us to restart the roll-forward recovery from the last checkpoint redone during rollforward recovery, if we happen to crash during the roll-forward recovery process.
ByteArray	getPreparedLog() the default for prepared log is always null for all the operations that don't have optionalData.
Formatable	getTransactionTable()
int	getTypeFormatId() Return my format identifier.
int	group() Checkpoint is a raw store operation
boolean	needsRedo(Transaction xact) Checkpoint does not need to be redone unless we are doing rollforward recovery.
void	readExternal(java.io.ObjectInput in)
long	redoLWM() Access attributes of the checkpoint record
void	releaseResource(Transaction xact) Checkpoint has not resource to release
java.lang.String	toString() DEBUG: Print self.
long	undoLWM()
void	writeExternal(java.io.ObjectOutput out)

Methods inherited from class java.lang.Object

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

Field Detail

redoLWM

protected long redoLWM

undoLWM

protected long undoLWM

transactionTable

protected Formatable transactionTable

Constructor Detail

CheckpointOperation

public CheckpointOperation(long redoLWM,
                   long undoLWM,
                   Formatable ttab)

CheckpointOperation

public CheckpointOperation()

Method Detail

writeExternal

public void writeExternal(java.io.ObjectOutput out)
                   throws java.io.IOException

Specified by:

writeExternal in interface java.io.Externalizable

Throws:

java.io.IOException

readExternal

public void readExternal(java.io.ObjectInput in)
                  throws java.io.IOException,
                         java.lang.ClassNotFoundException

Specified by:

readExternal in interface java.io.Externalizable

Throws:

java.io.IOException

java.lang.ClassNotFoundException

getTypeFormatId

public int getTypeFormatId()

Return my format identifier.

Specified by:

getTypeFormatId in interface TypedFormat

Returns:

The identifier. (A UUID stuffed in an array of 16 bytes).

doMe

public void doMe(Transaction xact,
        LogInstant instant,
        LimitObjectInput in)
          throws StandardException

Nothing to do unless we are rollforward recovery; Redoing of checkpoints during rollforward recovery allows us to restart the roll-forward recovery from the last checkpoint redone during rollforward recovery, if we happen to crash during the roll-forward recovery process. Another reason why we need to do this is dropped table stub files removed at checkpoint because the containerids may have been reused after a checkpoint if the system was rebooted.

Specified by:

doMe in interface Loggable

Parameters:

xact - the Transaction

instant - the log instant of this operation

in - optional data

Throws:

StandardException - Standard Derby policy.

getPreparedLog

public ByteArray getPreparedLog()

the default for prepared log is always null for all the operations that don't have optionalData. If an operation has optional data, the operation need to prepare the optional data for this method. Checkpoint has no optional data to write out

Specified by:

getPreparedLog in interface Loggable

needsRedo

public boolean needsRedo(Transaction xact)

Checkpoint does not need to be redone unless we are doing rollforward recovery.

Specified by:

needsRedo in interface Loggable

Parameters:

xact - The transaction trying to redo this operation

Returns:

true if operation needs redoing, false if not.

See Also:

Loggable.releaseResource(org.apache.derby.iapi.store.raw.Transaction)

releaseResource

public void releaseResource(Transaction xact)

Checkpoint has not resource to release

Specified by:

releaseResource in interface Loggable

group

public int group()

Checkpoint is a raw store operation

Specified by:

group in interface Loggable

redoLWM

public long redoLWM()

Access attributes of the checkpoint record

undoLWM

public long undoLWM()

getTransactionTable

public Formatable getTransactionTable()

toString

public java.lang.String toString()

DEBUG: Print self.

Overrides:

toString in class java.lang.Object