ExtremeAggComputer Class Reference

ExtremeAggComputer computes MIN/MAX, ignoring null values but returning null if the input is empty. More...

#include <AggComputerImpl.h>

Inheritance diagram for ExtremeAggComputer:


Public Member Functions
	ExtremeAggComputer (AggFunction aggFunctionInit, TupleAttributeDescriptor const &attrDesc)
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
void	copyInputToAccumulator (TupleDatum &accumulatorDatum, TupleDatum const &inputDatum)
Private Attributes
StoredTypeDescriptor const *	pTypeDescriptor
	Type descriptor used as comparison functor.
AggFunction	aggFunction
	Agg function implemented by this agg computer.
bool	isResultNull
	True until a non-null input value is seen.

Detailed Description

ExtremeAggComputer computes MIN/MAX, ignoring null values but returning null if the input is empty.

Definition at line 120 of file AggComputerImpl.h.

Constructor & Destructor Documentation

ExtremeAggComputer::ExtremeAggComputer	(	AggFunction	aggFunctionInit,
		TupleAttributeDescriptor const &	attrDesc
	)			`[explicit]`

Definition at line 222 of file AggComputer.cpp.

References aggFunction, TupleAttributeDescriptor::pTypeDescriptor, and pTypeDescriptor.

00225 {
00226     aggFunction = aggFunctionInit;
00227     pTypeDescriptor = attrDesc.pTypeDescriptor;
00228 }

Member Function Documentation

void ExtremeAggComputer::copyInputToAccumulator	(	TupleDatum &	accumulatorDatum,
		TupleDatum const &	inputDatum
	)			`[inline, private]`

Definition at line 235 of file AggComputer.cpp.

References TupleDatum::memCopyFrom().

Referenced by updateAccumulator().

00238 {
00239     // Use the utility function to copy from inputDatum's buffer to
00240     // accumulatorDatum.
00241     accumulatorDatum.memCopyFrom(inputDatum);
00242 }

void ExtremeAggComputer::clearAccumulator ( TupleDatum & accumulatorDatum ) [virtual]

Clears an accumulator.

Parameters:

accumulatorDatum

in-memory value to be cleared

Implements AggComputer.

Definition at line 230 of file AggComputer.cpp.

References isResultNull.

00231 {
00232     isResultNull = true;
00233 }

void ExtremeAggComputer::updateAccumulator	(	TupleDatum &	accumulatorDatum,
		TupleData const &	inputTuple
	)			`[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 244 of file AggComputer.cpp.

References AGG_FUNC_MIN, AGG_FUNC_SINGLE_VALUE, aggFunction, TupleDatum::cbData, StoredTypeDescriptor::compareValues(), copyInputToAccumulator(), AggComputer::iInputAttr, isResultNull, TupleDatum::pData, and pTypeDescriptor.

00247 {
00248     assert(iInputAttr != -1);
00249     TupleDatum const &inputDatum = inputTuple[iInputAttr];
00250     if (!inputDatum.pData) {
00251         // SQL2003 Part 2 Section 10.9 General Rule 4.a
00252         // TODO jvs 6-Oct-2005:  we're supposed to queue a warning
00253         // for null value eliminated in set function
00254         return;
00255     }
00256     if (isResultNull) {
00257         isResultNull = false;
00258         // first non-null input:  use it
00259         copyInputToAccumulator(accumulatorDatum, inputDatum);
00260         return;
00261     } else if (aggFunction == AGG_FUNC_SINGLE_VALUE) {
00262         throw FennelExcn(
00263             FennelResource::instance().scalarQueryReturnedMultipleRows());
00264     }
00265 
00266     // c = (input - accumulator)
00267     int c = pTypeDescriptor->compareValues(
00268         inputDatum.pData,
00269         inputDatum.cbData,
00270         accumulatorDatum.pData,
00271         accumulatorDatum.cbData);
00272     if (aggFunction == AGG_FUNC_MIN) {
00273         // invert comparison for MIN
00274         c = -c;
00275     }
00276     if (c <= 0) {
00277         // for MAX, input has to be greater than accumulator for accumulator
00278         // to be updated
00279         return;
00280     }
00281     copyInputToAccumulator(accumulatorDatum, inputDatum);
00282 }

void ExtremeAggComputer::computeOutput	(	TupleDatum &	outputDatum,
		TupleDatum const &	accumulatorDatum
	)			`[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 284 of file AggComputer.cpp.

References isResultNull, and TupleDatum::pData.

00287 {
00288     // Set output to alias accumulator value directly.
00289     outputDatum = accumulatorDatum;
00290     if (isResultNull) {
00291         outputDatum.pData = NULL;
00292     }
00293 }

void ExtremeAggComputer::initAccumulator	(	TupleDatum &	accumulatorDatumDest,
		TupleData const &	inputTuple
	)			`[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 295 of file AggComputer.cpp.

References AggComputer::iInputAttr, isResultNull, and TupleDatum::memCopyFrom().

00298 {
00299     accumulatorDatumDest.memCopyFrom(inputTuple[iInputAttr]);
00300     isResultNull = false;
00301 }

void ExtremeAggComputer::initAccumulator	(	TupleDatum &	accumulatorDatumSrc,
		TupleDatum &	accumulatorDatumDest
	)			`[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 303 of file AggComputer.cpp.

References isResultNull, and TupleDatum::memCopyFrom().

00306 {
00307     accumulatorDatumDest.memCopyFrom(accumulatorDatumSrc);
00308     isResultNull = false;
00309 }

void ExtremeAggComputer::updateAccumulator	(	TupleDatum &	accumulatorDatumSrc,
		TupleDatum &	accumulatorDatumDest,
		TupleData const &	inputTuple
	)			`[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 311 of file AggComputer.cpp.

References AGG_FUNC_MIN, AGG_FUNC_SINGLE_VALUE, aggFunction, TupleDatum::cbData, StoredTypeDescriptor::compareValues(), AggComputer::iInputAttr, TupleDatum::memCopyFrom(), TupleDatum::pData, and pTypeDescriptor.

00315 {
00316     if (aggFunction == AGG_FUNC_SINGLE_VALUE) {
00317         throw FennelExcn(
00318             FennelResource::instance().scalarQueryReturnedMultipleRows());
00319     }
00320 
00321     TupleDatum const &inputDatum = inputTuple[iInputAttr];
00322 
00323     if (!accumulatorDatumSrc.pData) {
00324         accumulatorDatumDest.memCopyFrom(inputDatum);
00325     } else if (inputDatum.pData) {
00326         // c = (input - accumulator)
00327         int c = pTypeDescriptor->compareValues(
00328             inputDatum.pData,
00329             inputDatum.cbData,
00330             accumulatorDatumSrc.pData,
00331             accumulatorDatumSrc.cbData);
00332         if (aggFunction == AGG_FUNC_MIN) {
00333             // invert comparison for MIN
00334             c = -c;
00335         }
00336         if (c <= 0) {
00337             // for MAX, input has to be greater than accumulator for accumulator
00338             // to be updated
00339             accumulatorDatumDest.memCopyFrom(accumulatorDatumSrc);
00340         } else {
00341             accumulatorDatumDest.memCopyFrom(inputDatum);
00342         }
00343     } else {
00344         accumulatorDatumDest.memCopyFrom(accumulatorDatumSrc);
00345     }
00346 }

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

StoredTypeDescriptor const* ExtremeAggComputer::pTypeDescriptor [private]

Type descriptor used as comparison functor.

Definition at line 126 of file AggComputerImpl.h.

Referenced by ExtremeAggComputer(), and updateAccumulator().

AggFunction ExtremeAggComputer::aggFunction [private]

Agg function implemented by this agg computer.

Definition at line 131 of file AggComputerImpl.h.

Referenced by ExtremeAggComputer(), and updateAccumulator().

bool ExtremeAggComputer::isResultNull [private]

True until a non-null input value is seen.

Definition at line 136 of file AggComputerImpl.h.

Referenced by clearAccumulator(), computeOutput(), initAccumulator(), and updateAccumulator().

int AggComputer::iInputAttr [protected, inherited]

Definition at line 50 of file AggComputer.h.

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

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

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

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

1.5.1

ExtremeAggComputer Class Reference

Public Member Functions

Static Public Member Functions

Protected Attributes

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation