Fennel: ExternalSortRunAccessor Class Reference (original) (raw)

ExternalSortRunAccessor manages I/O for storing runs and reading them back. More...

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

Inheritance diagram for ExternalSortRunAccessor:

List of all members.

Public Member Functions
ExternalSortRunAccessor (ExternalSortInfo &)
virtual ~ExternalSortRunAccessor ()
void initRead ()
Prepares this accessor to read (but does not specify a particular stored run yet).
void startRead (SharedSegStreamAllocation pStoredRunInit)
Begins reading a particular run.
void resetRead ()
Terminates read for the current run if any.
void storeRun (ExternalSortSubStream &subStream)
Stores a run.
SharedSegStreamAllocation getStoredRun ()
**Returns:**information about run created by storeRun()
void releaseResources ()
Releases any resources acquired by this accessor.
virtual ExternalSortFetchArray & bindFetchArray ()
Binds the fetch array which will be used implicitly by subsequent calls to fetch().
virtual ExternalSortRC fetch (uint nTuplesRequested)
Fetches tuples via the previously bound fetch array.
Private Member Functions
void clearFetch ()
Private Attributes
ExternalSortInfo & sortInfo
Global information.
TupleAccessor tupleAccessor
ExternalSortFetchArray fetchArray
Array used to return fetch results.
PBuffer ppTupleBuffers [EXTSORT_FETCH_ARRAY_SIZE]
Pointer array used to return fetch results.
SharedSegInputStream pSegInputStream
Helper used for reading stored runs.
SharedSegOutputStream pSegOutputStream
Helper used for writing stored runs.
SharedSegStreamAllocation pStoredRun
Information about run being accessed.

Detailed Description

ExternalSortRunAccessor manages I/O for storing runs and reading them back.

Definition at line 37 of file ExternalSortRunAccessor.h.

Constructor & Destructor Documentation

| ExternalSortRunAccessor::ExternalSortRunAccessor | ( | ExternalSortInfo & | | ) | [explicit] | | ------------------------------------------------ | - | ------------------------------------------------- | | - | ------------ |

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

Member Function Documentation

| void ExternalSortRunAccessor::clearFetch | ( | | ) | [inline, private] | | ---------------------------------------- | - | | - | ------------------- |

| void ExternalSortRunAccessor::initRead | ( | | ) | | -------------------------------------- | - | | - |

| void ExternalSortRunAccessor::resetRead | ( | | ) | | --------------------------------------- | - | | - |

Stores a run.

Parameters:

subStream substream whose contents are to be fetched and stored as a run

Definition at line 76 of file ExternalSortRunAccessor.cpp.

References ExternalSortSubStream::bindFetchArray(), ExternalSortInfo::externalSegmentAccessor, EXTSORT_ENDOFDATA, EXTSORT_FETCH_ARRAY_SIZE, EXTSORT_SUCCESS, ExternalSortSubStream::fetch(), fetchArray, TupleAccessor::getBufferByteCount(), SegOutputStream::newSegOutputStream(), SegStreamAllocation::newSegStreamAllocation(), ExternalSortFetchArray::nTuples, ExternalSortFetchArray::ppTupleBuffers, pSegOutputStream, pStoredRun, sortInfo, and tupleAccessor.

| void ExternalSortRunAccessor::releaseResources | ( | | ) | | ---------------------------------------------- | - | | - |

Fetches tuples via the previously bound fetch array.

Parameters:

nTuplesRequested maximum number of tuples to be returned from fetch (actual count may be less at callee's discretion; this does not indicate end of stream)

Returns:

result of fetch (either EXTSORT_ENDOFDATA or EXTSORT_SUCCESS)

Implements ExternalSortSubStream.

Definition at line 113 of file ExternalSortRunAccessor.cpp.

References ExecStream::checkAbort(), EXTSORT_ENDOFDATA, EXTSORT_FETCH_ARRAY_SIZE, EXTSORT_SUCCESS, fetchArray, TupleAccessor::getBufferByteCount(), ExternalSortFetchArray::nTuples, ppTupleBuffers, pSegInputStream, pStoredRun, sortInfo, ExternalSortInfo::stream, and tupleAccessor.

Member Data Documentation

Pointer array used to return fetch results.

These pointers get bound to contiguous tuples on stored run pages as they are read in.

Definition at line 58 of file ExternalSortRunAccessor.h.

Referenced by fetch().

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

Generated on Mon Jun 22 04:00:32 2009 for Fennel by doxygen 1.5.1