Class PhysicalPageOperation

java.lang.Object

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

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

All Implemented Interfaces:

Externalizable, Serializable, Formatable, TypedFormat, Loggable, RePreparable, Undoable

Direct Known Subclasses:

AllocPageOperation, ChainAllocPageOperation, CompressSpacePageOperation, CopyRowsOperation, InitPageOperation, InvalidatePageOperation, PurgeOperation, UpdateOperation

abstract class PhysicalPageOperation
extends PageBasicOperation
implements Undoable

An abstract class that is used for physical log operation. A physical log operation is one where the undo of the operation must be applied to the same page as the original operation, and the undo operation must store the byte image of the row(s) changed to its before image. (If a logical page operation happened to the page or if another transaction altered other rows on the page, the undo of this operation will only restore the before image of the row(s) affected).

Field Summary

Fields inherited from class PageBasicOperation

containerHdl, foundHere, page

Fields inherited from interface Loggable

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

Constructor Summary

Constructors

Constructor	Description
PhysicalPageOperation()
PhysicalPageOperation(BasePage page)

Method Summary

Modifier and Type	Method	Description
Compensation	generateUndo(Transaction xact, LimitObjectInput in)	Generate a Compensation (PageUndoOperation) that will rollback the changes of this page operation.
abstract void	undoMe(Transaction xact, BasePage undoPage, LogInstant CLRinstant, LimitObjectInput in)	Undo the change indicated by this log operation and optional data.

Methods inherited from class PageBasicOperation

findpage, getPage, getPageForRedoRecovery, getPageId, getPageVersion, getPreparedLog, group, needsRedo, readExternal, reclaimPrepareLocks, releaseResource, resetPageNumber, restoreMe, toString, writeExternal

Methods inherited from class Object

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

Methods inherited from interface Externalizable

readExternal, writeExternal

Methods inherited from interface Loggable

doMe, getPreparedLog, group, needsRedo, releaseResource

Methods inherited from interface TypedFormat

getTypeFormatId

Constructor Details

PhysicalPageOperation

PhysicalPageOperation(BasePage page)

PhysicalPageOperation

public PhysicalPageOperation()

Method Details

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(Transaction, LimitObjectInput)

undoMe

public abstract void undoMe(Transaction xact,
 BasePage undoPage,
 LogInstant CLRinstant,
 LimitObjectInput in)
                     throws StandardException,
IOException

Undo the change indicated by this log operation and optional data. The page the undo should apply to is the latched undoPage, the recordId is the same as the roll forward operation.
In this RawStore implementation, should only only be called via CompOp.doMe.

The available() method of in indicates how much data can be read, i.e. how much was originally written.

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:

IOException - Can be thrown by any of the methods of ObjectInput.

StandardException - Standard Derby policy.