ClickHouse/dbms/src/AggregateFunctions/AggregateFunctionCount.h
2019-02-13 15:53:36 +03:00

187 lines
5.8 KiB
C++

#pragma once
#include <IO/VarInt.h>
#include <IO/WriteHelpers.h>
#include <array>
#include <DataTypes/DataTypesNumber.h>
#include <Columns/ColumnNullable.h>
#include <AggregateFunctions/IAggregateFunction.h>
namespace DB
{
struct AggregateFunctionCountData
{
UInt64 count = 0;
};
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
}
/// Simply count number of calls.
class AggregateFunctionCount final : public IAggregateFunctionDataHelper<AggregateFunctionCountData, AggregateFunctionCount>
{
public:
AggregateFunctionCount(const DataTypes & argument_types_) : IAggregateFunctionDataHelper(argument_types_, {}) {}
String getName() const override { return "count"; }
DataTypePtr getReturnType() const override
{
return std::make_shared<DataTypeUInt64>();
}
void add(AggregateDataPtr place, const IColumn **, size_t, Arena *) const override
{
++data(place).count;
}
void merge(AggregateDataPtr place, ConstAggregateDataPtr rhs, Arena *) const override
{
data(place).count += data(rhs).count;
}
void serialize(ConstAggregateDataPtr place, WriteBuffer & buf) const override
{
writeVarUInt(data(place).count, buf);
}
void deserialize(AggregateDataPtr place, ReadBuffer & buf, Arena *) const override
{
readVarUInt(data(place).count, buf);
}
void insertResultInto(ConstAggregateDataPtr place, IColumn & to) const override
{
static_cast<ColumnUInt64 &>(to).getData().push_back(data(place).count);
}
/// May be used for optimization.
void addDelta(AggregateDataPtr place, UInt64 x) const
{
data(place).count += x;
}
const char * getHeaderFilePath() const override { return __FILE__; }
};
/// Simply count number of not-NULL values.
class AggregateFunctionCountNotNullUnary final : public IAggregateFunctionDataHelper<AggregateFunctionCountData, AggregateFunctionCountNotNullUnary>
{
public:
AggregateFunctionCountNotNullUnary(const DataTypePtr & argument, const Array & params)
: IAggregateFunctionDataHelper<AggregateFunctionCountData, AggregateFunctionCountNotNullUnary>({argument}, params)
{
if (!argument->isNullable())
throw Exception("Logical error: not Nullable data type passed to AggregateFunctionCountNotNullUnary", ErrorCodes::LOGICAL_ERROR);
}
String getName() const override { return "count"; }
DataTypePtr getReturnType() const override
{
return std::make_shared<DataTypeUInt64>();
}
void add(AggregateDataPtr place, const IColumn ** columns, size_t row_num, Arena *) const override
{
data(place).count += !static_cast<const ColumnNullable &>(*columns[0]).isNullAt(row_num);
}
void merge(AggregateDataPtr place, ConstAggregateDataPtr rhs, Arena *) const override
{
data(place).count += data(rhs).count;
}
void serialize(ConstAggregateDataPtr place, WriteBuffer & buf) const override
{
writeVarUInt(data(place).count, buf);
}
void deserialize(AggregateDataPtr place, ReadBuffer & buf, Arena *) const override
{
readVarUInt(data(place).count, buf);
}
void insertResultInto(ConstAggregateDataPtr place, IColumn & to) const override
{
static_cast<ColumnUInt64 &>(to).getData().push_back(data(place).count);
}
const char * getHeaderFilePath() const override { return __FILE__; }
};
/// Count number of calls where all arguments are not NULL.
class AggregateFunctionCountNotNullVariadic final : public IAggregateFunctionDataHelper<AggregateFunctionCountData, AggregateFunctionCountNotNullVariadic>
{
public:
AggregateFunctionCountNotNullVariadic(const DataTypes & arguments, const Array & params)
: IAggregateFunctionDataHelper<AggregateFunctionCountData, AggregateFunctionCountNotNullVariadic>(arguments, params)
{
number_of_arguments = arguments.size();
if (number_of_arguments == 1)
throw Exception("Logical error: single argument is passed to AggregateFunctionCountNotNullVariadic", ErrorCodes::LOGICAL_ERROR);
if (number_of_arguments > MAX_ARGS)
throw Exception("Maximum number of arguments for aggregate function with Nullable types is " + toString(size_t(MAX_ARGS)),
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
for (size_t i = 0; i < number_of_arguments; ++i)
is_nullable[i] = arguments[i]->isNullable();
}
String getName() const override { return "count"; }
DataTypePtr getReturnType() const override
{
return std::make_shared<DataTypeUInt64>();
}
void add(AggregateDataPtr place, const IColumn ** columns, size_t row_num, Arena *) const override
{
for (size_t i = 0; i < number_of_arguments; ++i)
if (is_nullable[i] && static_cast<const ColumnNullable &>(*columns[i]).isNullAt(row_num))
return;
++data(place).count;
}
void merge(AggregateDataPtr place, ConstAggregateDataPtr rhs, Arena *) const override
{
data(place).count += data(rhs).count;
}
void serialize(ConstAggregateDataPtr place, WriteBuffer & buf) const override
{
writeVarUInt(data(place).count, buf);
}
void deserialize(AggregateDataPtr place, ReadBuffer & buf, Arena *) const override
{
readVarUInt(data(place).count, buf);
}
void insertResultInto(ConstAggregateDataPtr place, IColumn & to) const override
{
static_cast<ColumnUInt64 &>(to).getData().push_back(data(place).count);
}
const char * getHeaderFilePath() const override { return __FILE__; }
private:
enum { MAX_ARGS = 8 };
size_t number_of_arguments = 0;
std::array<char, MAX_ARGS> is_nullable; /// Plain array is better than std::vector due to one indirection less.
};
}