Aggregation.h File Reference

Typed aggregation value, operator, and aggregator abstractions. More...

#include "postgres.h"
#include <variant>
#include <string>
#include <vector>
#include <cassert>
#include <memory>

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Classes
struct	AggValue
	A dynamically-typed aggregate value. More...
struct	Aggregator
	Abstract interface for an incremental aggregate accumulator. More...

Enumerations
enum class	ComparisonOperator {   EQ , NE , LE , LT ,   GE , GT }
	SQL comparison operators used in gate_cmp circuit gates. More...
enum class	AggregationOperator {   COUNT , SUM , MIN , MAX ,   AVG , AND , OR , CHOOSE ,   ARRAY_AGG , NONE }
	SQL aggregation functions tracked by ProvSQL. More...
enum class	ValueType {   INT , FLOAT , BOOLEAN , STRING ,   ARRAY_INT , ARRAY_FLOAT , ARRAY_BOOLEAN , ARRAY_STRING ,   NONE }
	Runtime type tag for aggregate values. More...

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

Detailed Description

Typed aggregation value, operator, and aggregator abstractions.

This header provides the type system used by ProvSQL's aggregate provenance evaluation:

• ComparisonOperator: the six standard SQL comparison operators, used by gate_cmp gates in the circuit.
• AggregationOperator: the SQL aggregation functions that ProvSQL tracks provenance for (COUNT, SUM, MIN, MAX, AVG, AND, OR, …).
• ValueType: the runtime type tag for aggregate values.
• AggValue: a tagged union holding one aggregate value of any supported type, built on std::variant.
• Aggregator: an abstract interface for stateful incremental accumulators, one per aggregation function/type combination.

The free functions getAggregationOperator() and makeAggregator() map PostgreSQL OIDs and operator/type pairs to the corresponding C++ objects.

Definition in file Aggregation.h.

Enumeration Type Documentation

AggregationOperator

enum class AggregationOperator

strong

SQL aggregation functions tracked by ProvSQL.

Enumerator
COUNT	COUNT(*) or COUNT(expr) → integer.
SUM	SUM → integer or float.
MIN	MIN → input type.
MAX	MAX → input type.
AVG	AVG → float.
AND	Boolean AND aggregate.
OR	Boolean OR aggregate.
CHOOSE	Arbitrary selection (pick one element).
ARRAY_AGG	Array aggregation.
NONE	No aggregation (returns NULL).

Definition at line 50 of file Aggregation.h.

ComparisonOperator

enum class ComparisonOperator

strong

SQL comparison operators used in gate_cmp circuit gates.

Enumerator
EQ	Equal (=).
NE	Not equal (<>).
LE	Less than or equal (<=).
LT	Less than (<).
GE	Greater than or equal (>=).
GT	Greater than (>).

Definition at line 38 of file Aggregation.h.

ValueType

enum class ValueType

strong

Runtime type tag for aggregate values.

Enumerator
INT	Signed 64-bit integer.
FLOAT	Double-precision float.
BOOLEAN	Boolean.
STRING	Text string.
ARRAY_INT	Array of integers.
ARRAY_FLOAT	Array of floats.
ARRAY_BOOLEAN	Array of booleans.
ARRAY_STRING	Array of strings.
NONE	No value (NULL).

Definition at line 66 of file Aggregation.h.

Function Documentation

cmpOpFromOid()

ComparisonOperator cmpOpFromOid	(	Oid	op_oid,
		bool &	ok )

Map a PostgreSQL comparison-operator OID to a ComparisonOperator.

The OID is the one stored in gate_cmp's info1 field (the OID of one of the six standard comparators =, <>, <, <=, >, >=). The translation goes via get_opname() so it is operand-type agnostic.

Parameters

[in]	op_oid	Comparison-operator OID.
[out]	ok	Set to true on a recognised comparator, false when op_oid does not resolve in pg_operator or its name is not one of the six standard ones.

Returns

The matching ComparisonOperator on success; an unspecified value (currently EQ) when ok is false.

Definition at line 66 of file Aggregation.cpp.

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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 316 of file Aggregation.cpp.

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