Fennel: SegPageEntryIter< EntryT > Class Template Reference (original) (raw)

SegPageEntryIter extends SegPageIter. More...

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

Inheritance diagram for SegPageEntryIter< EntryT >:

List of all members.

Public Member Functions
SegPageEntryIter ()
Constructor: iterator starts out singular.
SegPageEntryIter (uint nEntriesInit)
Constructor: iterator starts out singular.
void resize (uint nEntries)
Resizes the object to allow for storage of N pre-fetch entries.
void setPrefetchSource (SegPageEntryIterSource< EntryT > &prefetchSource)
Sets the pre-fetch source for this iterator.
void mapRange (SegmentAccessor const &segmentAccessor, PageId beginPageId, PageId endPageId=NULL_PAGE_ID)
Begins a new iteration.
std::pair< PageId, EntryT > & operator * ()
**Returns:**the current (PageId, EntryT) in the iteration
void operator++ ()
Moves to the next prefetched PageId.
void makeSingular ()
Aborts any iteration in progress and release all resources.
bool isSingular () const
**Returns:**true iff no iteration is in progress
PageId operator * () const
**Returns:**the current PageId in the iteration
void forcePrefetchReject ()
Forces the next pre-fetch request to be rejected.
Protected Member Functions
void initPrefetchQueue ()
Reads the pre-fetch parameters, sizes the pre-fetch queue, and initializes various state variables related to the queue.
void prefetchPage (PageId pageId)
Pre-fetches a specified page.
Protected Attributes
SegmentAccessor segmentAccessor
Accessor for the Segment containing the pages to be visited.
PageId endPageId
PageId at which to stop iteration.
std::vector< PageId > prefetchQueue
Fixed-size circular queue of prefetched PageIds, indexed by iFetch.
uint iFetch
Position in prefetchQueue.
bool atEnd
Whether end of iteration has been reached by prefetch (but not necessarily by fetch).
uint queueSize
Current size of the pre-fetch queue.
int nFreePageSlots
Number of slots available in the prefetchQueue.
Private Member Functions
void init ()
Initializes object.
void prefetchPages (PageId prevPageId, bool oneIter)
Determines a set of pages that should be pre-fetched and pre-fetches them.
Private Attributes
CircularBuffer< std::pair< PageId, EntryT > > entryQueue
Circular vector with the context-specific information associated with each pre-fetched page.
SegPageEntryIterSource< EntryT > * pPrefetchSource
Pointer to the source that provides the callback method that determines which pages to pre-fetch.

Detailed Description

template

class SegPageEntryIter< EntryT >

SegPageEntryIter extends SegPageIter.

Rather than pre-fetching successor pages, it takes a source parameter that provides a callback method that's used to determine which pages should be pre-fetched. The class is a template class, which allows context-specific information to be associated with each pre-fetched page.

Definition at line 42 of file SegPageEntryIter.h.

Constructor & Destructor Documentation

Member Function Documentation

template

void SegPageEntryIter< EntryT >::prefetchPages ( PageId prevPageId,
bool oneIter
) [private]

Determines a set of pages that should be pre-fetched and pre-fetches them.

Parameters:

prevPageId the id of the last page pre-fetched; only needed in the case where the entry queue is currently empty
oneIter if true, pre-fetch no more than one page

Definition at line 87 of file SegPageEntryIterImpl.h.

References SegPageIter::atEnd, CircularBuffer< T >::empty(), SegPageIter::endPageId, SegPageEntryIter< EntryT >::entryQueue, CircularBuffer< T >::getLastPos(), SegPageIter::nFreePageSlots, SegPageEntryIter< EntryT >::pPrefetchSource, SegPageIter::prefetchPage(), CircularBuffer< T >::push_back(), CircularBuffer< T >::reference_back(), and CircularBuffer< T >::spaceAvailable().

Referenced by SegPageEntryIter< EntryT >::mapRange(), and SegPageEntryIter< EntryT >::operator++().

Begins a new iteration.

Parameters:

segmentAccessor accessor for the segment containing the pages to visit
beginPageId the ID of the first page to visit; always set to NULL_PAGE_ID for this class, as the initial page is provided by the source parameter
endPageId the ID at which to end iteration; by default, this is NULL_PAGE_ID (representing the sentinel end of a chain) but the iteration (and prefetch) can be stopped earlier with some other known PageId; note that endPageId itself will not be prefetched

Reimplemented from SegPageIter.

Definition at line 69 of file SegPageEntryIterImpl.h.

References CircularBuffer< T >::clear(), SegPageIter::endPageId, SegPageEntryIter< EntryT >::entryQueue, SegPageIter::initPrefetchQueue(), NULL_PAGE_ID, SegmentAccessor::pCacheAccessor, SegPageEntryIter< EntryT >::prefetchPages(), SegmentAccessor::pSegment, and SegPageIter::segmentAccessor.

Referenced by BTreePrefetchSearchExecStream::innerSearchLoop(), LcsClusterReader::position(), and SegPageEntryIterTest::testIter().

template

| std::pair<PageId, EntryT>& SegPageEntryIter< EntryT >::operator * | ( | | ) | [inline] | | ------------------------------------------------------------------------------------------------ | - | | - | ---------- |

Moves to the next prefetched PageId.

An assertion violation results if called when positioned on endPageId.

Reimplemented from SegPageIter.

Definition at line 128 of file SegPageEntryIterImpl.h.

References SegPageIter::atEnd, CircularBuffer< T >::empty(), SegPageIter::endPageId, SegPageEntryIter< EntryT >::entryQueue, SegPageIter::iFetch, SegPageEntryIter< EntryT >::isSingular(), SegPageIter::nFreePageSlots, NULL_PAGE_ID, CircularBuffer< T >::pop_front(), SegPageEntryIter< EntryT >::prefetchPages(), SegPageIter::queueSize, and CircularBuffer< T >::reference_front().

template

| void SegPageEntryIter< EntryT >::makeSingular | ( | | ) | [inline] | | --------------------------------------------------------------------------- | - | | - | ---------- |

template

| bool SegPageEntryIter< EntryT >::isSingular | ( | | ) | const [inline] | | ------------------------------------------------------------------------- | - | | - | ---------------- |

| void SegPageIter::initPrefetchQueue | ( | | ) | [protected, inherited] | | ----------------------------------- | - | | - | ------------------------ |

Reads the pre-fetch parameters, sizes the pre-fetch queue, and initializes various state variables related to the queue.

Definition at line 66 of file SegPageIter.cpp.

References SegPageIter::atEnd, SegPageIter::currPageSlot, SegPageIter::forceReject, SegPageIter::iFetch, SegPageIter::nFreePageSlots, SegPageIter::noPrefetch, SegmentAccessor::pCacheAccessor, SegPageIter::prefetchPagesMax, SegPageIter::prefetchQueue, SegPageIter::prefetchThrottleRate, SegPageIter::queueSize, SegPageIter::segmentAccessor, and SegPageIter::throttleCount.

Referenced by SegPageIter::mapRange(), and SegPageEntryIter< EntryT >::mapRange().

void SegPageIter::prefetchPage ( PageId pageId ) [protected, inherited]

Pre-fetches a specified page.

Parameters:

pageId the id of the page to be pre-fetched

Definition at line 110 of file SegPageIter.cpp.

References SegPageIter::atEnd, SegPageIter::currPageSlot, SegPageIter::endPageId, SegPageIter::forceReject, SegPageIter::iFetch, SegPageIter::nFreePageSlots, SegPageIter::noPrefetch, NULL_BLOCK_ID, SegmentAccessor::pCacheAccessor, SegPageIter::prefetchPagesMax, SegPageIter::prefetchQueue, SegPageIter::prefetchThrottleRate, SegmentAccessor::pSegment, SegPageIter::queueSize, SegPageIter::segmentAccessor, and SegPageIter::throttleCount.

Referenced by SegPageIter::mapRange(), SegPageIter::operator++(), and SegPageEntryIter< EntryT >::prefetchPages().

| PageId SegPageIter::operator * | ( | | ) | const [inline, inherited] | | ------------------------------- | - | | - | --------------------------- |

Returns:

the current PageId in the iteration

Definition at line 156 of file SegPageIter.h.

| void SegPageIter::forcePrefetchReject | ( | | ) | [inherited] | | ------------------------------------- | - | | - | ------------- |

Member Data Documentation

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

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