Class AllocationCache

java.lang.Object

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

class AllocationCache
extends Object

An auxiliary object to cache the allocation information for a file container. Only a FileContainer should use this object

The allocation cache contains an array of AllocExtents and 3 arrays of longs:

1. ExtentPageNums[i] is the page number of the i'th extent
2. lowRange[i] is the smallest page number managed by extent i
3. hiRange[i] is the largest page number managed by extent i

Note thate extentPageNums and lowRange does not change once the extent has been created, but hiRange will change for the last extent as more pages are allocated.

Extents can be individually invalidated or the entire cache (all extends) can be invalidated at once.

MT - unsafe Synrhonized access to all methods must be enforced by the caller of AllocationCache

Field Summary

Fields

Modifier and Type	Field	Description
private long[]	extentPageNums
private AllocExtent[]	extents
private long[]	hiRange
private boolean[]	isDirty
private boolean	isValid
private long[]	lowRange
private int	numExtents

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AllocationCache()

Method Summary

Modifier and Type	Method	Description
protected void	dumpAllocationCache()	dump the allocation cache information
protected long	getAllocPageNumber(BaseContainerHandle handle, long pageNumber, long firstAllocPageNumber)	Get the page number for the allocation page that is managing this page number
protected SpaceInformation	getAllPageCounts(BaseContainerHandle handle, long firstAllocPageNumber)
protected long	getEstimatedPageCount(BaseContainerHandle handle, long firstAllocPageNumber)	returns estimated number of allocated pages
protected long	getLastPageNumber(BaseContainerHandle handle, long firstAllocPageNumber)	Get the last (allocated) page of the container
protected long	getLastValidPage(BaseContainerHandle handle, long firstAllocPageNumber)	Get the last valid page of the file container.
protected long	getNextValidPage(BaseContainerHandle handle, long pageNumber, long firstAllocPageNumber)
protected int	getPageStatus(BaseContainerHandle handle, long pageNumber, long firstAllocPageNumber)	Get the page status of a page
protected long	getUnfilledPageNumber(BaseContainerHandle handle, long firstAllocPageNumber, long pagenum)
private void	growArrays(int size)
protected void	invalidate()
protected void	invalidate(AllocPage allocPage, long allocPagenum)
protected void	invalidateLastExtent()
protected void	reset()
private void	setArrays(int i, AllocPage allocPage)
protected void	trackUnfilledPage(long pagenumber, boolean unfilled)	Set the page number to be unfilled
private void	validate(BaseContainerHandle handle, long firstAllocPageNumber)	Validate the cache, find all alloc pages and fill in the arrays

Methods inherited from class Object

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

Field Details

numExtents

private int numExtents

lowRange

private long[] lowRange

hiRange

private long[] hiRange

isDirty

private boolean[] isDirty

extents

private AllocExtent[] extents

extentPageNums

private long[] extentPageNums

isValid

private boolean isValid

Constructor Details

AllocationCache

protected AllocationCache()

Method Details

reset

protected void reset()

getAllocPageNumber

protected long getAllocPageNumber(BaseContainerHandle handle,
 long pageNumber,
 long firstAllocPageNumber)
                           throws StandardException

Get the page number for the allocation page that is managing this page number

Throws:

StandardException

getLastPageNumber

protected long getLastPageNumber(BaseContainerHandle handle,
 long firstAllocPageNumber)
                          throws StandardException

Get the last (allocated) page of the container

Throws:

StandardException

trackUnfilledPage

protected void trackUnfilledPage(long pagenumber,
 boolean unfilled)

Set the page number to be unfilled

getUnfilledPageNumber

protected long getUnfilledPageNumber(BaseContainerHandle handle,
 long firstAllocPageNumber,
 long pagenum)
                              throws StandardException

Throws:

StandardException

getEstimatedPageCount

protected long getEstimatedPageCount(BaseContainerHandle handle,
 long firstAllocPageNumber)
                              throws StandardException

returns estimated number of allocated pages

Throws:

StandardException

getAllPageCounts

protected SpaceInformation getAllPageCounts(BaseContainerHandle handle,
 long firstAllocPageNumber)
                                     throws StandardException

Throws:

StandardException

invalidate

protected void invalidate()

invalidate

protected void invalidate(AllocPage allocPage,
 long allocPagenum)
                   throws StandardException

Throws:

StandardException

invalidateLastExtent

protected void invalidateLastExtent()

getLastValidPage

protected long getLastValidPage(BaseContainerHandle handle,
 long firstAllocPageNumber)
                         throws StandardException

Get the last valid page of the file container. A valid page is one that is not deallocated or freed.

Throws:

StandardException

getNextValidPage

protected long getNextValidPage(BaseContainerHandle handle,
 long pageNumber,
 long firstAllocPageNumber)
                         throws StandardException

Throws:

StandardException

getPageStatus

protected int getPageStatus(BaseContainerHandle handle,
 long pageNumber,
 long firstAllocPageNumber)
                     throws StandardException

Get the page status of a page

Throws:

StandardException

validate

private void validate(BaseContainerHandle handle,
 long firstAllocPageNumber)
               throws StandardException

Validate the cache, find all alloc pages and fill in the arrays

Throws:

StandardException

setArrays

private void setArrays(int i,
 AllocPage allocPage)

growArrays

private void growArrays(int size)

dumpAllocationCache

protected void dumpAllocationCache()

dump the allocation cache information