ClickHouse/src/AggregateFunctions/AggregateFunctionArgMinMax.h

106 lines
3.6 KiB
C++

#pragma once
#include <base/StringRef.h>
#include <DataTypes/IDataType.h>
#include <AggregateFunctions/IAggregateFunction.h>
#include <AggregateFunctions/AggregateFunctionMinMaxAny.h> // SingleValueDataString used in embedded compiler
namespace DB
{
struct Settings;
namespace ErrorCodes
{
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
/// For possible values for template parameters, see AggregateFunctionMinMaxAny.h
template <typename ResultData, typename ValueData>
struct AggregateFunctionArgMinMaxData
{
using ResultData_t = ResultData;
using ValueData_t = ValueData;
ResultData result; // the argument at which the minimum/maximum value is reached.
ValueData value; // value for which the minimum/maximum is calculated.
static bool allocatesMemoryInArena()
{
return ResultData::allocatesMemoryInArena() || ValueData::allocatesMemoryInArena();
}
};
/// Returns the first arg value found for the minimum/maximum value. Example: argMax(arg, value).
template <typename Data>
class AggregateFunctionArgMinMax final : public IAggregateFunctionDataHelper<Data, AggregateFunctionArgMinMax<Data>>
{
private:
const DataTypePtr & type_res;
const DataTypePtr & type_val;
const SerializationPtr serialization_res;
const SerializationPtr serialization_val;
using Base = IAggregateFunctionDataHelper<Data, AggregateFunctionArgMinMax<Data>>;
public:
AggregateFunctionArgMinMax(const DataTypePtr & type_res_, const DataTypePtr & type_val_)
: Base({type_res_, type_val_}, {})
, type_res(this->argument_types[0])
, type_val(this->argument_types[1])
, serialization_res(type_res->getDefaultSerialization())
, serialization_val(type_val->getDefaultSerialization())
{
if (!type_val->isComparable())
throw Exception("Illegal type " + type_val->getName() + " of second argument of aggregate function " + getName()
+ " because the values of that data type are not comparable", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
}
String getName() const override
{
return StringRef(Data::ValueData_t::name()) == StringRef("min") ? "argMin" : "argMax";
}
DataTypePtr getReturnType() const override
{
return type_res;
}
void add(AggregateDataPtr __restrict place, const IColumn ** columns, size_t row_num, Arena * arena) const override
{
if (this->data(place).value.changeIfBetter(*columns[1], row_num, arena))
this->data(place).result.change(*columns[0], row_num, arena);
}
void merge(AggregateDataPtr __restrict place, ConstAggregateDataPtr rhs, Arena * arena) const override
{
if (this->data(place).value.changeIfBetter(this->data(rhs).value, arena))
this->data(place).result.change(this->data(rhs).result, arena);
}
void serialize(ConstAggregateDataPtr __restrict place, WriteBuffer & buf, std::optional<size_t> /* version */) const override
{
this->data(place).result.write(buf, *serialization_res);
this->data(place).value.write(buf, *serialization_val);
}
void deserialize(AggregateDataPtr __restrict place, ReadBuffer & buf, std::optional<size_t> /* version */, Arena * arena) const override
{
this->data(place).result.read(buf, *serialization_res, arena);
this->data(place).value.read(buf, *serialization_val, arena);
}
bool allocatesMemoryInArena() const override
{
return Data::allocatesMemoryInArena();
}
void insertResultInto(AggregateDataPtr __restrict place, IColumn & to, Arena *) const override
{
this->data(place).result.insertResultInto(to);
}
};
}