ClickHouse/dbms/src/AggregateFunctions/AggregateFunctionsUniq.cpp

#include <DB/AggregateFunctions/AggregateFunctionFactory.h>
#include <DB/AggregateFunctions/AggregateFunctionUniq.h>
#include <DB/AggregateFunctions/Helpers.h>

namespace DB
{

namespace
{

/** DataForVariadic - структура с данными, которая будет использоваться для агрегатной функции uniq от множества аргументов.
  * Отличается, например, тем, что использует тривиальную хэш-функцию, так как uniq от множества аргументов сначала самостоятельно их хэширует.
  */

template <typename Data, typename DataForVariadic>
AggregateFunctionPtr createAggregateFunctionUniq(const std::string & name, const DataTypes & argument_types)
{
	if (argument_types.size() == 1)
	{
		const IDataType & argument_type = *argument_types[0];

		AggregateFunctionPtr res(createWithNumericType<AggregateFunctionUniq, Data>(*argument_types[0]));

		if (res)
			return res;
		else if (typeid_cast<const DataTypeDate *>(&argument_type))
			return std::make_shared<AggregateFunctionUniq<DataTypeDate::FieldType, Data>>();
		else if (typeid_cast<const DataTypeDateTime *>(&argument_type))
			return std::make_shared<AggregateFunctionUniq<DataTypeDateTime::FieldType, Data>>();
		else if (typeid_cast<const DataTypeString *>(&argument_type) || typeid_cast<const DataTypeFixedString *>(&argument_type))
			return std::make_shared<AggregateFunctionUniq<String, Data>>();
		else if (typeid_cast<const DataTypeTuple *>(&argument_type))
			return std::make_shared<AggregateFunctionUniqVariadic<DataForVariadic, true>>();
		else
			throw Exception("Illegal type " + argument_types[0]->getName() + " of argument for aggregate function " + name,
				ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
	}
	else if (argument_types.size() > 1)
	{
		/// Если аргументов несколько, то среди них недопустимо наличие кортежей.
		for (const auto & type : argument_types)
			if (typeid_cast<const DataTypeTuple *>(type.get()))
				throw Exception("Tuple argument of function " + name + " must be the only argument",
					ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);

		return std::make_shared<AggregateFunctionUniqVariadic<DataForVariadic, false>>();
	}
	else
		throw Exception("Incorrect number of arguments for aggregate function " + name,
			ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
}

template <template <typename> class Data, typename DataForVariadic>
AggregateFunctionPtr createAggregateFunctionUniq(const std::string & name, const DataTypes & argument_types)
{
	if (argument_types.size() == 1)
	{
		const IDataType & argument_type = *argument_types[0];

		AggregateFunctionPtr res(createWithNumericType<AggregateFunctionUniq, Data>(*argument_types[0]));

		if (res)
			return res;
		else if (typeid_cast<const DataTypeDate *>(&argument_type))
			return std::make_shared<AggregateFunctionUniq<DataTypeDate::FieldType, Data<DataTypeDate::FieldType>>>();
		else if (typeid_cast<const DataTypeDateTime *>(&argument_type))
			return std::make_shared<AggregateFunctionUniq<DataTypeDateTime::FieldType, Data<DataTypeDateTime::FieldType>>>();
		else if (typeid_cast<const DataTypeString *>(&argument_type) || typeid_cast<const DataTypeFixedString *>(&argument_type))
			return std::make_shared<AggregateFunctionUniq<String, Data<String>>>();
		else if (typeid_cast<const DataTypeTuple *>(&argument_type))
			return std::make_shared<AggregateFunctionUniqVariadic<DataForVariadic, true>>();
		else
			throw Exception("Illegal type " + argument_types[0]->getName() + " of argument for aggregate function " + name,
				ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
	}
	else if (argument_types.size() > 1)
	{
		/// Если аргументов несколько, то среди них недопустимо наличие кортежей.
		for (const auto & type : argument_types)
			if (typeid_cast<const DataTypeTuple *>(type.get()))
				throw Exception("Tuple argument of function " + name + " must be the only argument",
					ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);

		return std::make_shared<AggregateFunctionUniqVariadic<DataForVariadic, false>>();
	}
	else
		throw Exception("Incorrect number of arguments for aggregate function " + name,
			ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
}

}

void registerAggregateFunctionsUniq(AggregateFunctionFactory & factory)
{
	factory.registerFunction("uniq",
		createAggregateFunctionUniq<AggregateFunctionUniqUniquesHashSetData, AggregateFunctionUniqUniquesHashSetDataForVariadic>);

	factory.registerFunction("uniqHLL12",
		createAggregateFunctionUniq<AggregateFunctionUniqHLL12Data, AggregateFunctionUniqHLL12DataForVariadic>);

	factory.registerFunction("uniqExact",
		createAggregateFunctionUniq<AggregateFunctionUniqExactData, AggregateFunctionUniqExactData<String>>);

	factory.registerFunction("uniqCombinedRaw",
		createAggregateFunctionUniq<AggregateFunctionUniqCombinedRawData, AggregateFunctionUniqCombinedRawData<UInt64>>);

	factory.registerFunction("uniqCombinedLinearCounting",
		createAggregateFunctionUniq<AggregateFunctionUniqCombinedLinearCountingData, AggregateFunctionUniqCombinedLinearCountingData<UInt64>>);

	factory.registerFunction("uniqCombinedBiasCorrected",
		createAggregateFunctionUniq<AggregateFunctionUniqCombinedBiasCorrectedData, AggregateFunctionUniqCombinedBiasCorrectedData<UInt64>>);

	factory.registerFunction("uniqCombined",
		createAggregateFunctionUniq<AggregateFunctionUniqCombinedData, AggregateFunctionUniqCombinedData<UInt64>>);
}

}