AllocationCache

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

java.lang.Object
  org.apache.derby.impl.store.raw.data.AllocationCache

class AllocationCache
extends java.lang.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:

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

private long[] extentPageNums


private AllocExtent[] extents


private long[] hiRange


private boolean[] isDirty


private boolean isValid


private long[] lowRange


private int numExtents


Constructor Summary

protected AllocationCache()


Method Summary

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 java.lang.Object

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

Field Detail

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 Detail