ClickHouse/src/AggregateFunctions/AggregateFunctionAggThrow.cpp
2021-05-26 14:58:31 +03:00

123 lines
3.2 KiB
C++

#include <memory>
#include <random>
#include <DataTypes/DataTypesNumber.h>
#include <Common/thread_local_rng.h>
#include <IO/ReadBuffer.h>
#include <IO/WriteBuffer.h>
#include <AggregateFunctions/IAggregateFunction.h>
#include <AggregateFunctions/AggregateFunctionFactory.h>
namespace DB
{
struct Settings;
namespace ErrorCodes
{
extern const int AGGREGATE_FUNCTION_THROW;
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
}
namespace
{
struct AggregateFunctionThrowData
{
bool allocated;
AggregateFunctionThrowData() : allocated(true) {}
~AggregateFunctionThrowData()
{
volatile bool * allocated_ptr = &allocated;
if (*allocated_ptr)
*allocated_ptr = false;
else
abort();
}
};
/** Throw on creation with probability specified in parameter.
* It will check correct destruction of the state.
* This is intended to check for exception safety.
*/
class AggregateFunctionThrow final : public IAggregateFunctionDataHelper<AggregateFunctionThrowData, AggregateFunctionThrow>
{
private:
Float64 throw_probability;
public:
AggregateFunctionThrow(const DataTypes & argument_types_, const Array & parameters_, Float64 throw_probability_)
: IAggregateFunctionDataHelper(argument_types_, parameters_), throw_probability(throw_probability_) {}
String getName() const override
{
return "aggThrow";
}
DataTypePtr getReturnType() const override
{
return std::make_shared<DataTypeUInt8>();
}
bool allocatesMemoryInArena() const override { return false; }
void create(AggregateDataPtr __restrict place) const override
{
if (std::uniform_real_distribution<>(0.0, 1.0)(thread_local_rng) <= throw_probability)
throw Exception("Aggregate function " + getName() + " has thrown exception successfully", ErrorCodes::AGGREGATE_FUNCTION_THROW);
new (place) Data;
}
void destroy(AggregateDataPtr __restrict place) const noexcept override
{
data(place).~Data();
}
void add(AggregateDataPtr, const IColumn **, size_t, Arena *) const override
{
}
void merge(AggregateDataPtr, ConstAggregateDataPtr, Arena *) const override
{
}
void serialize(ConstAggregateDataPtr, WriteBuffer & buf) const override
{
char c = 0;
buf.write(c);
}
void deserialize(AggregateDataPtr, ReadBuffer & buf, Arena *) const override
{
char c = 0;
buf.read(c);
}
void insertResultInto(AggregateDataPtr, IColumn & to, Arena *) const override
{
to.insertDefault();
}
};
}
void registerAggregateFunctionAggThrow(AggregateFunctionFactory & factory)
{
factory.registerFunction("aggThrow", [](const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
{
Float64 throw_probability = 1.0;
if (parameters.size() == 1)
throw_probability = parameters[0].safeGet<Float64>();
else if (parameters.size() > 1)
throw Exception("Aggregate function " + name + " cannot have more than one parameter", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
return std::make_shared<AggregateFunctionThrow>(argument_types, parameters, throw_probability);
});
}
}