Class AllocExtent

java.lang.Object

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

All Implemented Interfaces:

Externalizable, Serializable

public class AllocExtent
extends Object
implements Externalizable

An allocation extent row manages the page status of page in the extent. AllocExtent is externalizable and is written to the AllocPage directly, without being converted to a row first.

See Also:

• AllocPage
• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
private static final int	ALL_FREE
protected static final int	ALLOCATED_PAGE	public Per Page status
protected static final int	DEALLOCATED_PAGE
private long	extentEnd
private int	extentLength
private long	extentOffset
private long	extentStart
(package private) int	extentStatus
protected static final int	FREE_PAGE
(package private) FormatableBitSet	freePages
private static final int	HAS_DEALLOCATED
private static final int	HAS_FREE
private static final int	HAS_UNFILLED_PAGES
private static final int	KEEP_UNFILLED_PAGES
private static final int	NO_DEALLOC_PAGE_MAP
private int	preAllocLength
private int	reserved1
private long	reserved2
private long	reserved3
private static final int	RETIRED
(package private) FormatableBitSet	unFilledPages

Constructor Summary

Constructors

Modifier	Constructor	Description
	AllocExtent()
protected	AllocExtent(long offset, long start, int length, int pagesize, int maxlength)
protected	AllocExtent(AllocExtent original)

Method Summary

Modifier and Type	Method	Description
protected void	allocPage(long pagenum)	Allocate this page - this is called underneath the log record
protected boolean	canAddFreePage(long lastAllocatedPage)
private void	checkInRange(long pagenum)
protected int	compress(BaseContainerHandle owner, RawTransaction ntt, AllocPage alloc_page)	Compress free pages at end of this extent.
protected void	compressPages(int new_highest_page, int num_pages_truncated)
protected void	deallocPage(long pagenum)	Deallocate logical page pagenum - this is called underneath the log record. pagenum must be a page managed by this extent and it must be valid
protected int	getAllocatedPageCount()	Get the number of used page in this extent
protected long	getExtentEnd()
protected long	getFirstPagenum()	Get the first logical page number managed by this extent.
protected long	getFreePageNumber(long pnum)	Get a page number that is free
protected long	getLastPagenum()	Get the last logical page number managed by this extent.
protected long	getLastPreallocPagenum()	get the last preallocated pagenumber managed by this alloc page
protected long	getLastValidPageNumber()
protected long	getNextValidPageNumber(long prevPageNumber)
protected long	getPagenum(int bit_pos)	translate bit position in map to page number.
protected long	getPageOffset(long pagenum, int pagesize, boolean deallocOK)	Get the physical offset of pagenum.
protected int	getPageStatus(long pagenum)	Return the status of a particular page
protected int	getTotalPageCount()	Get the total number of pages in this extent
protected int	getUnfilledPageCount()	Get the number of unfilled pages in this extent
protected long	getUnfilledPageNumber(long pagenum)	Get a page number that is unfilled, pagenum is the last page that was rejected.
protected boolean	isRetired()	Return the status of this extent
protected static int	MAX_RANGE(int availspace)	Statically calculates how many pages this extent can manage given the availspace number of bytes to store this extent in if read/writeExternal changes, this must change too
private boolean	mayHaveFreePage()
void	readExternal(ObjectInput in)
private void	setExtentFreePageStatus(boolean hasFree)
protected void	setLastPreallocPagenum(long preAllocPagenum)	preallocated N pages, passed in the last preallocated page number.
protected String	toDebugString()
protected boolean	trackUnfilledPage(long pagenumber, boolean unfilled)
protected void	undoCompressPages(int new_highest_page, int num_pages_truncated)	Undo the compress space operation.
protected void	updateUnfilledPageInfo(AllocExtent inputExtent)
void	writeExternal(ObjectOutput out)

Methods inherited from class Object

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

Field Details

extentOffset

private long extentOffset

extentStart

private long extentStart

extentEnd

private long extentEnd

extentLength

private int extentLength

extentStatus

int extentStatus

preAllocLength

private int preAllocLength

reserved1

private int reserved1

reserved2

private long reserved2

reserved3

private long reserved3

HAS_DEALLOCATED

private static final int HAS_DEALLOCATED

See Also:

• Constant Field Values

HAS_FREE

private static final int HAS_FREE

See Also:

• Constant Field Values

ALL_FREE

private static final int ALL_FREE

See Also:

• Constant Field Values

HAS_UNFILLED_PAGES

private static final int HAS_UNFILLED_PAGES

See Also:

• Constant Field Values

KEEP_UNFILLED_PAGES

private static final int KEEP_UNFILLED_PAGES

See Also:

• Constant Field Values

NO_DEALLOC_PAGE_MAP

private static final int NO_DEALLOC_PAGE_MAP

See Also:

• Constant Field Values

RETIRED

private static final int RETIRED

See Also:

• Constant Field Values

ALLOCATED_PAGE

protected static final int ALLOCATED_PAGE

public Per Page status

See Also:

• Constant Field Values

DEALLOCATED_PAGE

protected static final int DEALLOCATED_PAGE

See Also:

• Constant Field Values

FREE_PAGE

protected static final int FREE_PAGE

See Also:

• Constant Field Values

freePages

FormatableBitSet freePages

unFilledPages

FormatableBitSet unFilledPages

Constructor Details

AllocExtent

protected AllocExtent(long offset,
 long start,
 int length,
 int pagesize,
 int maxlength)

AllocExtent

protected AllocExtent(AllocExtent original)

AllocExtent

public AllocExtent()

Method Details

MAX_RANGE

protected static int MAX_RANGE(int availspace)

Statically calculates how many pages this extent can manage given the availspace number of bytes to store this extent in if read/writeExternal changes, this must change too

writeExternal

public void writeExternal(ObjectOutput out)
                   throws IOException

Specified by:

writeExternal in interface Externalizable

Throws:

IOException

readExternal

public void readExternal(ObjectInput in)
                  throws IOException,
ClassNotFoundException

Specified by:

readExternal in interface Externalizable

Throws:

IOException

ClassNotFoundException

allocPage

protected void allocPage(long pagenum)
                  throws StandardException

Allocate this page - this is called underneath the log record

Throws:

StandardException - Standard Derby error policy

deallocPage

protected void deallocPage(long pagenum)
                    throws StandardException

Deallocate logical page pagenum - this is called underneath the log record. pagenum must be a page managed by this extent and it must be valid

Throws:

StandardException - Standard Derby error policy

compress

protected int compress(BaseContainerHandle owner,
 RawTransaction ntt,
 AllocPage alloc_page)
                throws StandardException

Compress free pages at end of this extent.

Search backward from end of extent and prepare data structures to return pages at end of extent to the OS. Returns the lowest page that can be returned to the OS.

Returns:

Return bit of page where all pages that follow can be returned to the OS.

Throws:

StandardException

compressPages

protected void compressPages(int new_highest_page,
 int num_pages_truncated)

undoCompressPages

protected void undoCompressPages(int new_highest_page,
 int num_pages_truncated)

Undo the compress space operation.

Undo of this operation doesn't really "undo" the operation, it just makes sure the data structures are ok after the undo. We are guaranteed at the point of the transaction doing the Undo of the compress space operation fixes up the bit maps to only point at pages within the new_highest_page range.

Prior to logging the compress space operation all pages greater than There are only 2 possibilities at this point: 1) the truncate of pages greater than new_highest_page happened before the abort took place. W 2)

getExtentEnd

protected long getExtentEnd()

getFreePageNumber

protected long getFreePageNumber(long pnum)

Get a page number that is free

getPageOffset

protected long getPageOffset(long pagenum,
 int pagesize,
 boolean deallocOK)
                      throws StandardException

Get the physical offset of pagenum. If deallocOK is true, then even if pagenum is deallocated, it is OK. If deallocOK is false, then an exception is thrown if pagenum is deallocated. An exception is always thrown if pagenum is a free page

Throws:

StandardException - Standard Derby error policy

isRetired

protected boolean isRetired()

Return the status of this extent

mayHaveFreePage

private boolean mayHaveFreePage()

setExtentFreePageStatus

private void setExtentFreePageStatus(boolean hasFree)

canAddFreePage

protected boolean canAddFreePage(long lastAllocatedPage)

getPageStatus

protected int getPageStatus(long pagenum)

Return the status of a particular page

getFirstPagenum

protected long getFirstPagenum()

Get the first logical page number managed by this extent.

getLastPagenum

protected long getLastPagenum()

Get the last logical page number managed by this extent.

getPagenum

protected long getPagenum(int bit_pos)

translate bit position in map to page number.

Returns:

The page number of this "bit" in the extent map.

getLastPreallocPagenum

protected long getLastPreallocPagenum()

get the last preallocated pagenumber managed by this alloc page

setLastPreallocPagenum

protected void setLastPreallocPagenum(long preAllocPagenum)

preallocated N pages, passed in the last preallocated page number.

getNextValidPageNumber

protected long getNextValidPageNumber(long prevPageNumber)

getLastValidPageNumber

protected long getLastValidPageNumber()

checkInRange

private void checkInRange(long pagenum)

updateUnfilledPageInfo

protected void updateUnfilledPageInfo(AllocExtent inputExtent)

trackUnfilledPage

protected boolean trackUnfilledPage(long pagenumber,
 boolean unfilled)

getUnfilledPageNumber

protected long getUnfilledPageNumber(long pagenum)

Get a page number that is unfilled, pagenum is the last page that was rejected.

getAllocatedPageCount

protected int getAllocatedPageCount()

Get the number of used page in this extent

getUnfilledPageCount

protected int getUnfilledPageCount()

Get the number of unfilled pages in this extent

getTotalPageCount

protected int getTotalPageCount()

Get the total number of pages in this extent

toDebugString

protected String toDebugString()