Apache Derby Database Engine and Embedded JDBC Driver 10.17.1.0 · org.apache.derby.impl.store.raw.data.AllocationCache

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:

ExtentPageNums[i] is the page number of the i'th extent
lowRange[i] is the smallest page number managed by extent i
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

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

Constructor Summary

Access	Constructor and Description
protected	AllocationCache()

Method Summary

Modifier and Type	Method and 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

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

extentPageNums	back to summary
private long[] extentPageNums

extents	back to summary
private AllocExtent[] extents

hiRange	back to summary
private long[] hiRange

isDirty	back to summary
private boolean[] isDirty

isValid	back to summary
private boolean isValid

lowRange	back to summary
private long[] lowRange

numExtents	back to summary
private int numExtents

Constructor Detail

AllocationCache	back to summary
protected AllocationCache()

Method Detail

dumpAllocationCache	back to summary
protected void dumpAllocationCache() dump the allocation cache information

getAllocPageNumber	back to summary
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

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

getEstimatedPageCount	back to summary
protected long getEstimatedPageCount(BaseContainerHandle handle, long firstAllocPageNumber) throws StandardException returns estimated number of allocated pages

getLastPageNumber	back to summary
protected long getLastPageNumber(BaseContainerHandle handle, long firstAllocPageNumber) throws StandardException Get the last (allocated) page of the container

getLastValidPage	back to summary
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.

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

getPageStatus	back to summary
protected int getPageStatus(BaseContainerHandle handle, long pageNumber, long firstAllocPageNumber) throws StandardException Get the page status of a page

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

growArrays	back to summary
private void growArrays(int size)

invalidate	back to summary
protected void invalidate()

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

invalidateLastExtent	back to summary
protected void invalidateLastExtent()

reset	back to summary
protected void reset()

setArrays	back to summary
private void setArrays(int i, AllocPage allocPage)

trackUnfilledPage	back to summary
protected void trackUnfilledPage(long pagenumber, boolean unfilled) Set the page number to be unfilled