SumAggComputer< T > Class Template Reference

SumAggComputer computes SUM(x), ignoring null values but returning null if the input is empty. More...

#include <AggComputerImpl.h>

Inheritance diagram for SumAggComputer< T >:


Public Member Functions
virtual void	clearAccumulator (TupleDatum &accumulatorDatum)
	Clears an accumulator.
virtual void	updateAccumulator (TupleDatum &accumulatorDatum, TupleData const &inputTuple)
	Updates an accumulator with a new input tuple.
virtual void	computeOutput (TupleDatum &outputDatum, TupleDatum const &accumulatorDatum)
	Computes an output based on accumulator state.
virtual void	initAccumulator (TupleDatum &accumulatorDatumDest, TupleData const &inputTuple)
	Initializes a new accumulator datum from an input tuple.
virtual void	initAccumulator (TupleDatum &accumulatorDatumSrc, TupleDatum &accumulatorDatumDest)
	Initializes a new accumulator datum from an existing accumulator datum.
virtual void	updateAccumulator (TupleDatum &accumulatorDatumSrc, TupleDatum &accumulatorDatumDest, TupleData const &inputTuple)
	Computes a new accumulator from an existing accumulator dataum and a new input tuple.
virtual void	setInputAttrIndex (uint iInputAttrIndex)
	Sets the attribute index from which this computer should read input values in source tuples.
Static Public Member Functions
static AggComputer *	newAggComputer (AggFunction aggFunction, TupleAttributeDescriptor const *pAttrDesc)
	Virtual constructor.
Protected Attributes
int	iInputAttr
Private Member Functions
T &	interpretDatum (TupleDatum &datum)
T const &	interpretDatum (TupleDatum const &datum)
Private Attributes
bool	isResultNull
	True until a non-null input value is seen.

Detailed Description

template<class T>
class SumAggComputer< T >

SumAggComputer computes SUM(x), ignoring null values but returning null if the input is empty.

Definition at line 180 of file AggComputerImpl.h.

Member Function Documentation

template<class T>

T& SumAggComputer< T >::interpretDatum ( TupleDatum & datum ) [inline, private]

Definition at line 187 of file AggComputerImpl.h.

References TupleDatum::cbData, and TupleDatum::pData.

Referenced by SumAggComputer< T >::clearAccumulator(), and SumAggComputer< T >::updateAccumulator().

00188     {
00189         assert(datum.cbData == sizeof(T));
00190         assert(datum.pData);
00191         return *reinterpret_cast<T *>(const_cast<PBuffer>(datum.pData));
00192     }

template<class T>

T const& SumAggComputer< T >::interpretDatum ( TupleDatum const & datum ) [inline, private]

Definition at line 194 of file AggComputerImpl.h.

References TupleDatum::cbData, and TupleDatum::pData.

00195     {
00196         assert(datum.cbData == sizeof(T));
00197         assert(datum.pData);
00198         return *reinterpret_cast<T const *>(datum.pData);
00199     }

template<class T>

virtual void SumAggComputer< T >::clearAccumulator ( TupleDatum & accumulatorDatum ) [inline, virtual]

Clears an accumulator.

Parameters:

accumulatorDatum

in-memory value to be cleared

Implements AggComputer.

Definition at line 203 of file AggComputerImpl.h.

References SumAggComputer< T >::interpretDatum(), SumAggComputer< T >::isResultNull, and sum().

00204     {
00205         T &sum = interpretDatum(accumulatorDatum);
00206         sum = 0;
00207 
00208         isResultNull = true;
00209     }

template<class T>

virtual void SumAggComputer< T >::updateAccumulator	(	TupleDatum &	accumulatorDatum,
		TupleData const &	inputTuple
	)			`[inline, virtual]`

Updates an accumulator with a new input tuple.

Parameters:

	accumulatorDatum	in-memory value to be updated
	inputTuple	source for update; no references to this data should be retained after this method returns

Implements AggComputer.

Definition at line 212 of file AggComputerImpl.h.

References AggComputer::iInputAttr, SumAggComputer< T >::interpretDatum(), SumAggComputer< T >::isResultNull, TupleDatum::pData, and sum().

00215     {
00216         assert(iInputAttr != -1);
00217         TupleDatum const &inputDatum = inputTuple[iInputAttr];
00218         if (!inputDatum.pData) {
00219             // SQL2003 Part 2 Section 10.9 General Rule 4.a
00220             // TODO jvs 6-Oct-2005:  we're supposed to queue a warning
00221             // for null value eliminated in set function
00222             return;
00223         } else {
00224             isResultNull = false;
00225         }
00226         T &sum = interpretDatum(accumulatorDatum);
00227         if (inputDatum.pData) {
00228             T input = interpretDatum(inputDatum);
00229             // TODO jvs 6-Oct-2005:  overflow check
00230             sum += input;
00231         }
00232     }

template<class T>

virtual void SumAggComputer< T >::computeOutput	(	TupleDatum &	outputDatum,
		TupleDatum const &	accumulatorDatum
	)			`[inline, virtual]`

Computes an output based on accumulator state.

Parameters:

	outputDatum	receives reference to computed output in preparation for marshalling result
	accumulatorDatum	final in-memory accumulator state

Implements AggComputer.

Definition at line 235 of file AggComputerImpl.h.

References SumAggComputer< T >::isResultNull, and TupleDatum::pData.

00238     {
00239         // Set output to alias accumulator value directly.
00240         outputDatum = accumulatorDatum;
00241         if (isResultNull) {
00242             outputDatum.pData = NULL;
00243         }
00244     }

template<class T>

virtual void SumAggComputer< T >::initAccumulator	(	TupleDatum &	accumulatorDatumDest,
		TupleData const &	inputTuple
	)			`[inline, virtual]`

Initializes a new accumulator datum from an input tuple.

Parameters:

	accumulatorDatumDest	in-memory value to be updated. Memory needs to be associated with this datum by the caller.
	inputTuple	source for update; no references to this data should be retained after this method returns

Implements AggComputer.

Definition at line 246 of file AggComputerImpl.h.

References AggComputer::iInputAttr, SumAggComputer< T >::isResultNull, and TupleDatum::memCopyFrom().

00249     {
00250         accumulatorDatumDest.memCopyFrom(inputTuple[iInputAttr]);
00251         isResultNull = false;
00252     }

template<class T>

virtual void SumAggComputer< T >::initAccumulator	(	TupleDatum &	accumulatorDatumSrc,
		TupleDatum &	accumulatorDatumDest
	)			`[inline, virtual]`

Initializes a new accumulator datum from an existing accumulator datum.

Parameters:

	accumulatorDatumSrc	the existing accumulator datum
	accumulatorDatumDest	the new accumulator datum. Memory needs to be associated with this datum by the caller.

Implements AggComputer.

Definition at line 254 of file AggComputerImpl.h.

References SumAggComputer< T >::isResultNull, and TupleDatum::memCopyFrom().

00257     {
00258         accumulatorDatumDest.memCopyFrom(accumulatorDatumSrc);
00259         isResultNull = false;
00260     }

template<class T>

virtual void SumAggComputer< T >::updateAccumulator	(	TupleDatum &	accumulatorDatumSrc,
		TupleDatum &	accumulatorDatumDest,
		TupleData const &	inputTuple
	)			`[inline, virtual]`

Computes a new accumulator from an existing accumulator dataum and a new input tuple.

Parameters:

	accumulatorDatumSrc	the existing accumulator datum
	accumulatorDatumDest	the new accumulator datum. memory needs to be associated with this datum by the caller.
	inputTuple	source for update; no references to this data should be retained after this method returns

Implements AggComputer.

Definition at line 262 of file AggComputerImpl.h.

References AggComputer::iInputAttr, SumAggComputer< T >::interpretDatum(), TupleDatum::memCopyFrom(), and TupleDatum::pData.

00266     {
00267         TupleDatum const &inputDatum = inputTuple[iInputAttr];
00268 
00269         if (!accumulatorDatumSrc.pData) {
00270             accumulatorDatumDest.memCopyFrom(inputDatum);
00271         } else {
00272             T sumSrc = interpretDatum(accumulatorDatumSrc);
00273             T &sumDest = interpretDatum(accumulatorDatumDest);
00274 
00275             if (inputDatum.pData) {
00276                 T sumInput = interpretDatum(inputDatum);
00277                 sumDest = sumSrc + sumInput;
00278             } else {
00279                 sumDest = sumSrc;
00280             }
00281         }
00282     }

AggComputer * AggComputer::newAggComputer	(	AggFunction	aggFunction,
		TupleAttributeDescriptor const *	pAttrDesc
	)			`[static, inherited]`

Virtual constructor.

Parameters:

	aggFunction	function for which to construct a computer
	pAttrDesc	descriptor for input attribute, or NULL for no input attribute (as in COUNT(*))

Definition at line 34 of file AggComputer.cpp.

References AGG_FUNC_COUNT, AGG_FUNC_MAX, AGG_FUNC_MIN, AGG_FUNC_SINGLE_VALUE, AGG_FUNC_SUM, STANDARD_TYPE_DOUBLE, STANDARD_TYPE_INT_16, STANDARD_TYPE_INT_32, STANDARD_TYPE_INT_64, STANDARD_TYPE_INT_8, STANDARD_TYPE_REAL, STANDARD_TYPE_UINT_16, STANDARD_TYPE_UINT_32, STANDARD_TYPE_UINT_64, and STANDARD_TYPE_UINT_8.

Referenced by SortedAggExecStream::newAggComputer(), and LhxAggExecStream::setAggComputers().

00037 {
00038     switch (aggFunction) {
00039     case AGG_FUNC_COUNT:
00040         if (pAttrDesc) {
00041             return new CountNullableAggComputer();
00042         } else {
00043             return new CountStarAggComputer();
00044         }
00045     case AGG_FUNC_SUM:
00046         assert(pAttrDesc);
00047         // TODO jvs 6-Oct-2005:  gotta use some of that template
00048         // metaprogramming mumbo jumbo to get rid of this
00049         switch (pAttrDesc->pTypeDescriptor->getOrdinal()) {
00050         case STANDARD_TYPE_INT_8:
00051             return new SumAggComputer<int8_t>();
00052         case STANDARD_TYPE_UINT_8:
00053             return new SumAggComputer<uint8_t>();
00054         case STANDARD_TYPE_INT_16:
00055             return new SumAggComputer<int16_t>();
00056         case STANDARD_TYPE_UINT_16:
00057             return new SumAggComputer<uint16_t>();
00058         case STANDARD_TYPE_INT_32:
00059             return new SumAggComputer<int32_t>();
00060         case STANDARD_TYPE_UINT_32:
00061             return new SumAggComputer<uint32_t>();
00062         case STANDARD_TYPE_INT_64:
00063             return new SumAggComputer<int64_t>();
00064         case STANDARD_TYPE_UINT_64:
00065             return new SumAggComputer<uint64_t>();
00066         case STANDARD_TYPE_REAL:
00067             return new SumAggComputer<float>();
00068         case STANDARD_TYPE_DOUBLE:
00069             return new SumAggComputer<double>();
00070         }
00071     case AGG_FUNC_MIN:
00072     case AGG_FUNC_MAX:
00073     case AGG_FUNC_SINGLE_VALUE:
00074         assert(pAttrDesc);
00075         return new ExtremeAggComputer(aggFunction, *pAttrDesc);
00076     }
00077     permAssert(false);
00078 }

void AggComputer::setInputAttrIndex ( uint iInputAttrIndex ) [virtual, inherited]

Sets the attribute index from which this computer should read input values in source tuples.

Parameters:

iInputAttrIndex

0-based tuple attribute index

Reimplemented in LbmRepeatingAggComputer.

Definition at line 85 of file AggComputer.cpp.

References AggComputer::iInputAttr.

Referenced by LbmRepeatingAggComputer::setInputAttrIndex().

00086 {
00087     iInputAttr = iInputAttrInit;
00088 }

Member Data Documentation

template<class T>

bool SumAggComputer< T >::isResultNull [private]

True until a non-null input value is seen.

Definition at line 185 of file AggComputerImpl.h.

Referenced by SumAggComputer< T >::clearAccumulator(), SumAggComputer< T >::computeOutput(), SumAggComputer< T >::initAccumulator(), and SumAggComputer< T >::updateAccumulator().

int AggComputer::iInputAttr [protected, inherited]

Definition at line 50 of file AggComputer.h.

Referenced by AggComputer::AggComputer(), CountStarAggComputer::clearAccumulator(), SumAggComputer< T >::initAccumulator(), ExtremeAggComputer::initAccumulator(), CountNullableAggComputer::initAccumulator(), CountStarAggComputer::initAccumulator(), AggComputer::setInputAttrIndex(), SumAggComputer< T >::updateAccumulator(), ExtremeAggComputer::updateAccumulator(), and CountNullableAggComputer::updateAccumulator().

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

/home/pub/open/dev/fennel/exec/AggComputerImpl.h

Generated on Mon Jun 22 04:00:47 2009 for Fennel by

1.5.1

SumAggComputer< T > Class Template Reference

Public Member Functions

Static Public Member Functions

Protected Attributes

Private Member Functions

Private Attributes

Detailed Description

template<class T> class SumAggComputer< T >

Member Function Documentation

Member Data Documentation

template<class T>
class SumAggComputer< T >