AggComputer Class Reference

Abstract base class representing computation of a single aggregate function over a collection of scalar values all having the same group key. More...

#include <AggComputer.h>

Inheritance diagram for AggComputer:

CountAggComputer ExtremeAggComputer LbmRepeatingAggComputer SumAggComputer< T > CountNullableAggComputer CountStarAggComputer List of all members.

Public Member Functions

 AggComputer ()
virtual ~AggComputer ()
virtual void setInputAttrIndex (uint iInputAttrIndex)
 Sets the attribute index from which this computer should read input values in source tuples.
virtual void clearAccumulator (TupleDatum &accumulatorDatum)=0
 Clears an accumulator.
virtual void updateAccumulator (TupleDatum &accumulatorDatum, TupleData const &inputTuple)=0
 Updates an accumulator with a new input tuple.
virtual void computeOutput (TupleDatum &outputDatum, TupleDatum const &accumulatorDatum)=0
 Computes an output based on accumulator state.
virtual void initAccumulator (TupleDatum &accumulatorDatumDest, TupleData const &inputTuple)=0
 Initializes a new accumulator datum from an input tuple.
virtual void initAccumulator (TupleDatum &accumulatorDatumSrc, TupleDatum &accumulatorDatumDest)=0
 Initializes a new accumulator datum from an existing accumulator datum.
virtual void updateAccumulator (TupleDatum &accumulatorDatumSrc, TupleDatum &accumulatorDatumDest, TupleData const &inputTuple)=0
 Computes a new accumulator from an existing accumulator dataum and a new input tuple.

Static Public Member Functions

static AggComputer * newAggComputer (AggFunction aggFunction, TupleAttributeDescriptor const *pAttrDesc)
 Virtual constructor.

Protected Attributes

int iInputAttr

Detailed Description

Abstract base class representing computation of a single aggregate function over a collection of scalar values all having the same group key.

In order to be used for more complex functions such as AVG which require compound accumulator state, it needs to be extended to allow AggComputer to collaborate with its caller in defining the accumulator tuple. Luckily, Farrago rewrites AVG to SUM/COUNT.

Author:
John V. Sichi
Version:
Id
//open/dev/fennel/exec/AggComputer.h#10

Definition at line 47 of file AggComputer.h.

Constructor & Destructor Documentation

AggComputer::AggComputer (  )  [explicit]

Definition at line 80 of file AggComputer.cpp.

References iInputAttr.

00081 {
00082     iInputAttr = -1;
00083 }

AggComputer::~AggComputer (  )  [virtual]

Definition at line 90 of file AggComputer.cpp.

00091 {
00092 }

Member Function Documentation

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

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]

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 iInputAttr.

Referenced by LbmRepeatingAggComputer::setInputAttrIndex().

00086 {
00087     iInputAttr = iInputAttrInit;
00088 }

virtual void AggComputer::clearAccumulator ( TupleDatum &  accumulatorDatum  )  [pure virtual]

Clears an accumulator.

Parameters:
accumulatorDatum in-memory value to be cleared

Implemented in CountStarAggComputer, CountNullableAggComputer, ExtremeAggComputer, SumAggComputer< T >, and LbmRepeatingAggComputer.

Referenced by LbmRepeatingAggComputer::clearAccumulator().

virtual void AggComputer::updateAccumulator ( TupleDatum &  accumulatorDatum,
TupleData const &  inputTuple 
) [pure 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

Implemented in CountStarAggComputer, CountNullableAggComputer, ExtremeAggComputer, SumAggComputer< T >, and LbmRepeatingAggComputer.

Referenced by LbmRepeatingAggComputer::updateAccumulator().

virtual void AggComputer::computeOutput ( TupleDatum &  outputDatum,
TupleDatum const &  accumulatorDatum 
) [pure 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

Implemented in CountAggComputer, ExtremeAggComputer, SumAggComputer< T >, and LbmRepeatingAggComputer.

Referenced by LbmRepeatingAggComputer::computeOutput().

virtual void AggComputer::initAccumulator ( TupleDatum &  accumulatorDatumDest,
TupleData const &  inputTuple 
) [pure 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

Implemented in CountStarAggComputer, CountNullableAggComputer, ExtremeAggComputer, SumAggComputer< T >, and LbmRepeatingAggComputer.

virtual void AggComputer::initAccumulator ( TupleDatum &  accumulatorDatumSrc,
TupleDatum &  accumulatorDatumDest 
) [pure 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.

Implemented in CountStarAggComputer, CountNullableAggComputer, ExtremeAggComputer, SumAggComputer< T >, and LbmRepeatingAggComputer.

virtual void AggComputer::updateAccumulator ( TupleDatum &  accumulatorDatumSrc,
TupleDatum &  accumulatorDatumDest,
TupleData const &  inputTuple 
) [pure 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

Implemented in CountStarAggComputer, CountNullableAggComputer, ExtremeAggComputer, SumAggComputer< T >, and LbmRepeatingAggComputer.

Member Data Documentation

int AggComputer::iInputAttr [protected]

Definition at line 50 of file AggComputer.h.

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

The documentation for this class was generated from the following files:
Generated on Mon Jun 22 04:00:24 2009 for Fennel by  doxygen 1.5.1