Fennel: Segment Class Reference (original) (raw)

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Segment is a virtualization layer for allocating and accessing pages of device storage via the cache. More...

#include <[Segment.h](Segment%5F8h-source.html)>

Inheritance diagram for Segment:

List of all members.

Detailed Description

Segment is a virtualization layer for allocating and accessing pages of device storage via the cache.

See the design docs for more detail.

Definition at line 43 of file Segment.h.

Member Typedef Documentation

Member Enumeration Documentation

Enumeration of the possible orderings of PageIds returned from allocatePageId.

The enumeration is from weakest to strongest ordering, and should not be changed.

Enumerator:

Definition at line 105 of file Segment.h.

Constructor & Destructor Documentation

| Segment::~Segment | ( | | ) | [virtual] | | ------------------ | - | | - | ----------- |

Destructor.

As a side-effect of closing a segment, a call to checkpoint() with CHECKPOINT_FLUSH_AND_UNMAP is made so that all pages are guaranteed to be unmapped before destruction.

Definition at line 40 of file Segment.cpp.

References ClosableObject::close().

00041 { 00042 close(); 00043 }

Member Function Documentation

| void Segment::setUsablePageSize | ( | uint | | ) | [protected] | | ------------------------------- | - | ----------------------------------------------------------------- | | - | ------------- |

| void Segment::closeImpl | ( | | ) | [protected, virtual] | | ----------------------- | - | | - | ---------------------- |

| uint Segment::getFullPageSize | ( | | ) | const | | ------------------------------------------------------------------------------------------ | - | | - | ----- |

| uint Segment::getUsablePageSize | ( | | ) | const [inline] | | -------------------------------------------------------------------------------------------- | - | | - | ---------------- |

| void Segment::initForUse | ( | | ) | [virtual] | | ------------------------ | - | | - | ----------- |

| virtual BlockNum Segment::getAllocatedSizeInPages | ( | | ) | [pure virtual] | | ----------------------------------------------------------------------------------------------------- | - | | - | ---------------- |

| virtual BlockNum Segment::getNumPagesOccupiedHighWater | ( | | ) | [pure virtual] | | ---------------------------------------------------------------------------------------------------------- | - | | - | ---------------- |

| virtual BlockNum Segment::getNumPagesExtended | ( | | ) | [pure virtual] | | ------------------------------------------------------------------------------------------------- | - | | - | ---------------- |

Returns:

tracing segment associated with this segment if tracing is turned on; otherwise, returns the segment itself

Definition at line 50 of file Segment.cpp.

References pTracingSegment.

Referenced by VersionedRandomAllocationSegment::allocateAllocNodes(), RandomAllocationSegment::allocateFromExtent(), RandomAllocationSegment::allocateFromNewExtent(), RandomAllocationSegment::allocatePageId(), VersionedRandomAllocationSegment::backupAllocationNodes(), VersionedRandomAllocationSegment::chainPageEntries(), SnapshotRandomAllocationSegment::commitChanges(), VersionedRandomAllocationSegment::copyPageEntryFromTemp(), VersionedRandomAllocationSegment::copyPageEntryToTemp(), RandomAllocationSegmentBase::deallocatePageId(), VersionedRandomAllocationSegment::findAllocPageIdForRead(), RandomAllocationSegmentBase::format(), RandomAllocationSegmentBase::formatPageExtentsTemplate(), RandomAllocationSegmentBase::freePageEntryTemplate(), RandomAllocationSegment::getExtAllocPageIdForRead(), VersionedRandomAllocationSegment::getOldestTxnId(), VersionedRandomAllocationSegment::getOldPageIds(), RandomAllocationSegmentBase::getPageEntryCopyTemplate(), RandomAllocationSegment::getSegAllocPageIdForRead(), VersionedRandomAllocationSegment::getTempAllocNodePage(), getTracingListener(), VersionedRandomAllocationSegment::locateDataPages(), VersionedRandomAllocationSegment::restoreFromBackup(), SnapshotRandomAllocationSegment::rollbackChanges(), RandomAllocationSegment::setPageSuccessor(), VersionedRandomAllocationSegment::updateExtentEntry(), and VersionedRandomAllocationSegment::validateFreePageCount().

00051 { 00052 SharedSegment sharedPtr = pTracingSegment.lock(); 00053 if (sharedPtr && sharedPtr.get()) { 00054 return sharedPtr; 00055 } else { 00056 return shared_from_this(); 00057 } 00058 }

Sets the tracing segment associated with this segment.

Parameters:

Definition at line 60 of file Segment.cpp.

References pTracingSegment.

| virtual AllocationOrder Segment::getAllocationOrder | ( | | ) | const [pure virtual] | | --------------------------------------------------------------------------------------------------------- | - | | - | ---------------------- |

| virtual BlockId Segment::translatePageId | ( | PageId | | ) | [pure virtual] | | ---------------------------------------- | - | ------ | | - | ---------------- |

| virtual PageId Segment::translateBlockId | ( | BlockId | | ) | [pure virtual] | | ---------------------------------------- | - | ------- | | - | ---------------- |

Allocates a page without locking it into memory.

Parameters:

Returns:

the PageId of the allocated page, or NULL_PAGE_ID if none could be allocated

Implemented in CircularSegment, DelegatingSegment, DynamicDelegatingSegment, LinearDeviceSegment, LinearViewSegment, RandomAllocationSegment, ScratchSegment, SnapshotRandomAllocationSegment, TracingSegment, and VersionedRandomAllocationSegment.

Referenced by ensureAllocatedSize().

Deallocates a range of pages allocated from this segment.

Some segment implementations may impose restrictions on the range (e.g. individual pages only, entire segment truncation only, start-ranges, or end-ranges). The interpretation of the range may also vary by segment (e.g. for a LINEAR_ALLOCATION segment, it's a simple linear PageId range, while for a RANDOM_ALLOCATION segment, successors could be used).

Depending on the circumstances, it may be the responsibility of the segment to discard the corresponding blocks from the cache. The details vary by segment implementation.

Parameters:

Implemented in CircularSegment, DelegatingSegment, DynamicDelegatingSegment, LinearDeviceSegment, LinearViewSegment, RandomAllocationSegmentBase, ScratchSegment, SnapshotRandomAllocationSegment, TracingSegment, VersionedRandomAllocationSegment, and VersionedSegment.

Determines whether a page can be updated in-place, and if so, prepares the page for update.

Parameters:

Returns:

NULL_PAGE_ID if the page can be updated in place; otherwise, the pageId of the page that should be used when updates are made to the page

Reimplemented in DelegatingSegment, DynamicDelegatingSegment, LinearViewSegment, and SnapshotRandomAllocationSegment.

Definition at line 148 of file Segment.cpp.

References NULL_PAGE_ID.

| bool Segment::isWriteVersioned | ( | | ) | [virtual] | | ------------------------------ | - | | - | ----------- |

Constructs a linear PageId based on a linear page number.

Definition at line 348 of file Segment.h.

Referenced by RandomAllocationSegmentBase::allocateFromLockedExtentTemplate(), ScratchSegment::allocatePageId(), LinearViewSegment::allocatePageId(), LinearDeviceSegment::allocatePageId(), CircularSegment::allocatePageId(), RandomAllocationSegmentBase::getExtentAllocPageId(), VersionedRandomAllocationSegment::getOldPageIds(), RandomAllocationSegmentBase::getSegAllocPageId(), Database::init(), VersionedRandomAllocationSegment::locateDataPages(), SegmentTestBase::lockPage(), SegmentTestBase::prefetchPage(), SegPageIterTest::testBoundedIter(), SegPageEntryIterTest::testBoundedIter(), ScratchSegment::translateBlockId(), LinearViewSegment::translateBlockId(), LinearDeviceSegment::translateBlockId(), CircularSegment::translateBlockId(), and CircularSegment::translatePageId().

00349 { 00350 return PageId(iPage); 00351 }

Obtains the linear page number from a linear PageId.

Definition at line 353 of file Segment.h.

References opaqueToInt().

Referenced by CircularSegment::CircularSegment(), LinearDeviceSegment::deallocatePageRange(), CircularSegment::deallocatePageRange(), isLinearPageIdAllocated(), CircularSegment::isPageIdAllocated(), SegmentTestBase::lockPage(), SegInputStream::readPrevBuffer(), setLinearPageSuccessor(), RandomAllocationSegmentBase::splitPageId(), CircularSegment::translateBlockId(), ScratchSegment::translatePageId(), LinearViewSegment::translatePageId(), LinearDeviceSegment::translatePageId(), CircularSegment::translatePageId(), and LinearViewSegment::updatePage().

Retrieves the tracing wrapper corresponding to this listener if tracing is turned on.

Otherwise, returns this listener itself.

Returns:

tracing segment corresponding to a listener

Implements MappedPageListener.

Definition at line 65 of file Segment.cpp.

References getTracingSegment().

Receives notification from CacheImpl the first time a page becomes dirty after it has been mapped (but before the contents have changed).

Allows some logging action to be taken; for example, making a backup copy of the unmodified page contents. Note that when called for a newly allocated page, the page contents are invalid. Because it is implied that the calling thread already has an exclusive lock on the page, no cache locks are held when called.

Parameters:

Reimplemented in DelegatingSegment, DynamicDelegatingSegment, SnapshotRandomAllocationSegment, TracingSegment, VersionedSegment, and WALSegment.

Definition at line 41 of file MappedPageListener.cpp.

Receives notification from CacheImpl just before a dirty page is flushed to disk.

Allows some logging action to be taken; for example, flushing corresponding write-ahead log pages, or storing a checksum in the page header. Called with the page mutex held, so the implementation must take care to avoid deadlock.

Parameters:

Reimplemented in DelegatingSegment, DynamicDelegatingSegment, and TracingSegment.

Definition at line 45 of file MappedPageListener.cpp.

Receives notification that a page has been flushed during a checkpoint.

Also determines if the listener on the page needs to be reset.

Note that if the page listener is reset, that page may not be unmapped during a CHECKPOINT_FLUSH_AND_UNMAP checkpoint call.

This method should be called immediately after the page flush has completed while the checkpoint is still in progress.

Parameters:

Returns:

NULL if the listener on the page does not need to be reset; otherwise, returns the listener that the page should be reset to

Reimplemented in SnapshotRandomAllocationSegment, and TracingSegment.

Definition at line 62 of file MappedPageListener.cpp.

00064 { 00065 return NULL; 00066 }

| bool ClosableObject::isClosed | ( | | ) | const [inline, inherited] | | ----------------------------- | - | | - | --------------------------- |

Returns:

whether the object has been closed

Definition at line 58 of file ClosableObject.h.

| void ClosableObject::close | ( | | ) | [inherited] | | -------------------------- | - | | - | ------------- |

Closes this object, releasing any unallocated resources.

Reimplemented in CollectExecStream, CorrelationJoinExecStream, LcsClusterAppendExecStream, and LcsClusterReplaceExecStream.

Definition at line 39 of file ClosableObject.cpp.

References ClosableObject::closeImpl(), and ClosableObject::needsClose.

Referenced by CacheImpl< PageT, VictimPolicyT >::allocatePages(), LcsRowScanBaseExecStream::closeImpl(), ExecStreamGraphImpl::closeImpl(), FlatFileBuffer::open(), ClosableObjectDestructor::operator()(), and ~Segment().

Member Data Documentation

Cache managing pages of this segment.

Definition at line 62 of file Segment.h.

Referenced by VersionedRandomAllocationSegment::allocateAllocNodes(), RandomAllocationSegmentBase::allocateFromExtentTemplate(), RandomAllocationSegmentBase::allocateFromNewExtentTemplate(), RandomAllocationSegmentBase::allocatePageIdFromSegment(), VersionedRandomAllocationSegment::backupAllocationNodes(), VersionedRandomAllocationSegment::chainPageEntries(), VersionedRandomAllocationSegment::copyPageEntryFromTemp(), VersionedRandomAllocationSegment::copyPageEntryToTemp(), RandomAllocationSegmentBase::deallocatePageId(), VersionedRandomAllocationSegment::deallocateSinglePage(), VersionedRandomAllocationSegment::deferDeallocation(), VersionedSegment::delegatedCheckpoint(), SnapshotRandomAllocationSegment::delegatedCheckpoint(), delegatedCheckpoint(), RandomAllocationSegmentBase::format(), RandomAllocationSegmentBase::formatPageExtentsTemplate(), RandomAllocationSegmentBase::freePageEntryTemplate(), getCache(), getFullPageSize(), VersionedRandomAllocationSegment::getOldestTxnId(), VersionedRandomAllocationSegment::getOldPageIds(), RandomAllocationSegmentBase::getPageEntryCopyTemplate(), VersionedRandomAllocationSegment::getTempAllocNodePage(), VersionedRandomAllocationSegment::initPageEntry(), VersionedRandomAllocationSegment::locateDataPages(), VersionedSegment::notifyPageDirty(), VersionedSegment::recover(), VersionedRandomAllocationSegment::restoreFromBackup(), RandomAllocationSegmentBase::setPageSuccessorTemplate(), RandomAllocationSegmentBase::tallySegAllocNodePages(), VersionedRandomAllocationSegment::uncommittedDeallocation(), VersionedRandomAllocationSegment::updateExtentEntry(), VersionedRandomAllocationSegment::updatePageEntry(), VersionedRandomAllocationSegment::updateTempPageEntry(), and VersionedRandomAllocationSegment::validateFreePageCount().

The documentation for this class was generated from the following files:

• /home/pub/open/dev/fennel/segment/Segment.h
• /home/pub/open/dev/fennel/segment/Segment.cpp

Generated on Mon Jun 22 04:00:45 2009 for Fennel by 1.5.1