org.apache.derby.impl.store.raw.data

Class CompressSpacePageOperation

java.lang.Object

org.apache.derby.impl.store.raw.data.CompressSpacePageOperation

All Implemented Interfaces:

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

Direct Known Subclasses:

CompressSpacePageOperation10_2

public class CompressSpacePageOperation
extends java.lang.Object

Log operation to implement compressing space from a container and returning it to the operating system.

See Also:

Serialized Form

Field Summary

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
CompressSpacePageOperation() Public Methods of Formatable interface.

Method Summary

Modifier and Type	Method and Description
void	doMe(Transaction tran, LogInstant instant, LimitObjectInput in) Compress space from container.
org.apache.derby.impl.store.raw.data.BasePage	findpage(Transaction xact) Find the page the operation applies to and latch it, this only uses the segmentId, containerId, and pageId stored in this log record to find the page.
Compensation	generateUndo(Transaction xact, LimitObjectInput in) Generate a Compensation (PageUndoOperation) that will rollback the changes of this page operation.
Page	getPage()
long	getPageVersion()
ByteArray	getPreparedLog() the default for optional data is set to null.
int	getTypeFormatId() Return my format identifier.
int	group() A page operation is a RAWSTORE log record
boolean	needsRedo(Transaction xact) Returns true if this op should be redone during recovery redo, if so, get and latched the page.
void	readExternal(java.io.ObjectInput in)
void	reclaimPrepareLocks(Transaction t, LockingPolicy locking_policy) reclaim locks associated with the changes in this log record.
void	releaseResource(Transaction xact) Release latched page and any other resources acquired during a previous findpage, safe to call multiple times.
void	restoreMe(Transaction xact, org.apache.derby.impl.store.raw.data.BasePage undoPage, LogInstant CLRinstant, LimitObjectInput in) Undo the change indicated by this log operation and optional data.
java.lang.String	toString() debug
void	undoMe(Transaction xact, org.apache.derby.impl.store.raw.data.BasePage undoPage, LogInstant CLRInstant, LimitObjectInput in) Compress space undo.
void	writeExternal(java.io.ObjectOutput out)

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

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

getPreparedLog, group, needsRedo, releaseResource

Constructor Detail

CompressSpacePageOperation

public CompressSpacePageOperation()

Public Methods of Formatable interface.

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 - error reading from log stream

java.lang.ClassNotFoundException - cannot read object from input

getTypeFormatId

public int getTypeFormatId()

Return my format identifier.

Returns:

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

doMe

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

Compress space from container.

Compress the indicate space from the container, returning the free pages to the OS. Update the allocation page to reflect the file change.

Parameters:

tran - transaction doing the operation.

instant - log instant for this operation.

in - unused by this log operation.

Throws:

StandardException - Standard exception policy.

undoMe

public void undoMe(Transaction xact,
                   org.apache.derby.impl.store.raw.data.BasePage undoPage,
                   LogInstant CLRInstant,
                   LimitObjectInput in)
            throws StandardException

Compress space undo.

Parameters:

xact - the Transaction doing the rollback

undoPage - the page to rollback changes on

CLRInstant - the log instant of this (PageUndo) operation

in - optional data for the rollback operation

Throws:

StandardException - Thrown by methods I call

See Also:

PhysicalPageOperation.undoMe(org.apache.derby.iapi.store.raw.Transaction, org.apache.derby.impl.store.raw.data.BasePage, org.apache.derby.iapi.store.raw.log.LogInstant, org.apache.derby.iapi.services.io.LimitObjectInput)

restoreMe

public void restoreMe(Transaction xact,
                      org.apache.derby.impl.store.raw.data.BasePage undoPage,
                      LogInstant CLRinstant,
                      LimitObjectInput in)

Undo the change indicated by this log operation and optional data. The page the undo should apply to is the latched undoPage. The undoPage must be the same page as the doMe page and the undo operation must restore the before image of the row that changed.
this can only be used under special circumstances: namely table level locking, and no internal or nested transaction, and all operations are rollec back with restoreMe instead of undoMe.
This method is here to support BeforeImageLogging

Parameters:

xact - the Transaction doing the rollback

undoPage - the page to rollback changes on

CLRinstant - the log instant of this (PageUndo) operation

in - optional data for the rollback operation

toString

public java.lang.String toString()

debug

generateUndo

public Compensation generateUndo(Transaction xact,
                                 LimitObjectInput in)
                          throws StandardException

Generate a Compensation (PageUndoOperation) that will rollback the changes of this page operation. If this Page operation cannot or need not be rolled back (redo only), overwrite this function to return null.

Note
For operation that needs logical undo, use LogicalUndoOperation instead This implementation just finds the same page that the PageOperation was applied on - i.e., only works for undo on the same page.

During recovery redo, the logging system is page oriented and will use the pageID stored in the PageUndoOperation to find the page. The page will be latched and released using the default findpage and releaseResource - this.releaseResource() will still be called so it has to know not to release any resource it did not acquire.

Specified by:

generateUndo in interface Undoable

Parameters:

xact - the transaction doing the compensating

in - optional input

Returns:

the compensation operation that will rollback this change

Throws:

StandardException - Standard Derby policy.

See Also:

PageBasicOperation, Undoable.generateUndo(org.apache.derby.iapi.store.raw.Transaction, org.apache.derby.iapi.services.io.LimitObjectInput)

needsRedo

public final boolean needsRedo(Transaction xact)
                        throws StandardException

Returns true if this op should be redone during recovery redo, if so, get and latched the page.

Specified by:

needsRedo in interface Loggable

Parameters:

xact - The transaction trying to redo this operation

Returns:

true if operation needs redoing, false if not.

Throws:

StandardException - Standard Derby policy.

See Also:

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

releaseResource

public void releaseResource(Transaction xact)

Release latched page and any other resources acquired during a previous findpage, safe to call multiple times. In this RawStore implementataion, resource is acquired by a log operation in one of two places

during runtime or recovery undo in PageOperation.generateUndo() during recovery redo in PageBasicOperation.needsRedo()

Specified by:

releaseResource in interface Loggable

group

public int group()

A page operation is a RAWSTORE log record

Specified by:

group in interface Loggable

getPreparedLog

public ByteArray getPreparedLog()
                         throws StandardException

the default for optional data is set to null. If an operation has optional data, the operation need to prepare the optional data for this method. WARNING: If a log operation extends this class, and the operation has optional data, it MUST overwrite this method to return a ByteArray that contains the optional data.

Specified by:

getPreparedLog in interface Loggable

Throws:

StandardException - Standard Derby policy.

reclaimPrepareLocks

public void reclaimPrepareLocks(Transaction t,
                                LockingPolicy locking_policy)
                         throws StandardException

reclaim locks associated with the changes in this log record.

Specified by:

reclaimPrepareLocks in interface RePreparable

Throws:

StandardException - Standard exception policy.

findpage

public final org.apache.derby.impl.store.raw.data.BasePage findpage(Transaction xact)
                                                             throws StandardException

Find the page the operation applies to and latch it, this only uses the segmentId, containerId, and pageId stored in this log record to find the page.

Returns:

null if container is dropped and committed (possibly stubbified), else return the latched page

Throws:

StandardException - Standard Derby policy.

getPage

public final Page getPage()

getPageVersion

public final long getPageVersion()