Aggregation.cpp File Reference

Aggregation operator and accumulator implementations. More...

#include "Aggregation.h"
#include <string>
#include <stdexcept>
#include "utils/lsyscache.h"
#include "utils/elog.h"
#include "provsql_error.h"

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Classes
struct	NoneAgg
	Aggregator that ignores all inputs and always returns NULL. More...
struct	False<... >
struct	StandardAgg< T >
	Base aggregator template for scalar types (int, float, bool, string). More...
struct	SumAgg< T >
	Aggregator implementing SUM for integer or float types. More...
struct	MinAgg< T >
	Aggregator implementing MIN for integer or float types. More...
struct	MaxAgg< T >
	Aggregator implementing MAX for integer or float types. More...
struct	AndAgg
	Aggregator implementing boolean AND (returns false if any input is false). More...
struct	OrAgg
	Aggregator implementing boolean OR (returns true if any input is true). More...
struct	ChooseAgg< T >
	Aggregator implementing CHOOSE (returns the first non-NULL input). More...
struct	AvgAgg< T >
	Aggregator implementing AVG; always returns a float result. More...
struct	ArrayAgg< T >
	Aggregator implementing ARRAY_AGG; collects all non-NULL inputs into an array. More...

Functions
AggregationOperator	getAggregationOperator (Oid oid)
	Map a PostgreSQL aggregate function OID to an AggregationOperator.
std::unique_ptr< Aggregator >	makeAggregator (AggregationOperator op, ValueType t)
	Create a concrete Aggregator for the given operator and value type.

Detailed Description

Aggregation operator and accumulator implementations.

Implements the two factory functions declared in Aggregation.h:

• getAggregationOperator(): maps a PostgreSQL aggregate function OID (looked up by name via get_func_name()) to an AggregationOperator enum value.
• makeAggregator(): constructs a concrete Aggregator subclass for the given operator/type combination.

Each aggregation function × value-type combination has its own Aggregator subclass defined locally in this file (e.g. SumAggregator<long>, MinAggregator<double>, ArrayAggregator<std::string>, etc.).

Definition in file Aggregation.cpp.

Function Documentation

getAggregationOperator()

AggregationOperator getAggregationOperator

(

Oid

oid

)

Map a PostgreSQL aggregate function OID to an AggregationOperator.

Parameters

oid	OID of the aggregate function (e.g. F_COUNT_ANY, F_SUM_INT4).

Returns

The corresponding AggregationOperator.

Definition at line 29 of file Aggregation.cpp.

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makeAggregator()

std::unique_ptr< Aggregator > makeAggregator	(	AggregationOperator	op,
		ValueType	t
	)

Create a concrete Aggregator for the given operator and value type.

Parameters

op	The aggregation function to implement.
t	The type of input values that will be accumulated.

Returns

A heap-allocated Aggregator, or nullptr if the combination is not supported.

Definition at line 294 of file Aggregation.cpp.

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