Fennel: AggComputer Class Reference (original) (raw)

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](AggComputer%5F8h-source.html)>

Inheritance diagram for AggComputer:

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.

Version:

Id

//open/dev/fennel/exec/AggComputer.h#10

Definition at line 47 of file AggComputer.h.

Constructor & Destructor Documentation

| AggComputer::AggComputer | ( | | ) | [explicit] | | ------------------------ | - | | - | ------------ |

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

Member Function Documentation

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().

void AggComputer::setInputAttrIndex ( uint iInputAttrIndex ) [virtual]
virtual void AggComputer::clearAccumulator ( TupleDatum & accumulatorDatum ) [pure virtual]
virtual void AggComputer::updateAccumulator ( TupleDatum & accumulatorDatum,
TupleData const & inputTuple
) [pure virtual]
virtual void AggComputer::computeOutput ( TupleDatum & outputDatum,
TupleDatum const & accumulatorDatum
) [pure virtual]
virtual void AggComputer::initAccumulator ( TupleDatum & accumulatorDatumDest,
TupleData const & inputTuple
) [pure virtual]
virtual void AggComputer::initAccumulator ( TupleDatum & accumulatorDatumSrc,
TupleDatum & accumulatorDatumDest
) [pure virtual]
virtual void AggComputer::updateAccumulator ( TupleDatum & accumulatorDatumSrc,
TupleDatum & accumulatorDatumDest,
TupleData const & inputTuple
) [pure virtual]

Member Data Documentation

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