ClickHouse/src/AggregateFunctions/AggregateFunctionUniqCombined.h
2021-10-02 10:13:14 +03:00

246 lines
8.2 KiB
C++

#pragma once
#include <base/bit_cast.h>
#include <Common/CombinedCardinalityEstimator.h>
#include <Common/SipHash.h>
#include <Common/typeid_cast.h>
#include <Common/assert_cast.h>
#include <DataTypes/DataTypeTuple.h>
#include <DataTypes/DataTypeUUID.h>
#include <DataTypes/DataTypesNumber.h>
#include <AggregateFunctions/IAggregateFunction.h>
#include <AggregateFunctions/UniqCombinedBiasData.h>
#include <AggregateFunctions/UniqVariadicHash.h>
#include <Columns/ColumnVector.h>
#include <Columns/ColumnsNumber.h>
namespace DB
{
struct Settings;
namespace detail
{
/** Hash function for uniqCombined/uniqCombined64 (based on Ret).
*/
template <typename T, typename Ret>
struct AggregateFunctionUniqCombinedTraits
{
static Ret hash(T x)
{
if constexpr (sizeof(T) > sizeof(UInt64))
return static_cast<Ret>(DefaultHash64<T>(x));
else
return static_cast<Ret>(intHash64(x));
}
};
template <typename Ret>
struct AggregateFunctionUniqCombinedTraits<UInt128, Ret>
{
static Ret hash(UInt128 x)
{
return sipHash64(x);
}
};
template <typename Ret>
struct AggregateFunctionUniqCombinedTraits<Float32, Ret>
{
static Ret hash(Float32 x)
{
UInt64 res = bit_cast<UInt64>(x);
return static_cast<Ret>(intHash64(res));
}
};
template <typename Ret>
struct AggregateFunctionUniqCombinedTraits<Float64, Ret>
{
static Ret hash(Float64 x)
{
UInt64 res = bit_cast<UInt64>(x);
return static_cast<Ret>(intHash64(res));
}
};
}
// Unlike HashTableGrower always grows to power of 2.
struct UniqCombinedHashTableGrower : public HashTableGrower<>
{
void increaseSize() { ++size_degree; }
};
template <typename Key, UInt8 K>
struct AggregateFunctionUniqCombinedDataWithKey
{
// TODO(ilezhankin): pre-generate values for |UniqCombinedBiasData|,
// at the moment gen-bias-data.py script doesn't work.
// We want to migrate from |HashSet| to |HyperLogLogCounter| when the sizes in memory become almost equal.
// The size per element in |HashSet| is sizeof(Key)*2 bytes, and the overall size of |HyperLogLogCounter| is 2^K * 6 bits.
// For Key=UInt32 we can calculate: 2^X * 4 * 2 ≤ 2^(K-3) * 6 ⇒ X ≤ K-4.
using Set = CombinedCardinalityEstimator<Key, HashSet<Key, TrivialHash, UniqCombinedHashTableGrower>, 16, K - 5 + (sizeof(Key) == sizeof(UInt32)), K, TrivialHash, Key>;
Set set;
};
template <typename Key>
struct AggregateFunctionUniqCombinedDataWithKey<Key, 17>
{
using Set = CombinedCardinalityEstimator<Key,
HashSet<Key, TrivialHash, UniqCombinedHashTableGrower>,
16,
12 + (sizeof(Key) == sizeof(UInt32)),
17,
TrivialHash,
Key,
HyperLogLogBiasEstimator<UniqCombinedBiasData>,
HyperLogLogMode::FullFeatured>;
Set set;
};
template <typename T, UInt8 K, typename HashValueType>
struct AggregateFunctionUniqCombinedData : public AggregateFunctionUniqCombinedDataWithKey<HashValueType, K>
{
};
/// For String keys, 64 bit hash is always used (both for uniqCombined and uniqCombined64),
/// because of backwards compatibility (64 bit hash was already used for uniqCombined).
template <UInt8 K, typename HashValueType>
struct AggregateFunctionUniqCombinedData<String, K, HashValueType> : public AggregateFunctionUniqCombinedDataWithKey<UInt64 /*always*/, K>
{
};
template <typename T, UInt8 K, typename HashValueType>
class AggregateFunctionUniqCombined final
: public IAggregateFunctionDataHelper<AggregateFunctionUniqCombinedData<T, K, HashValueType>, AggregateFunctionUniqCombined<T, K, HashValueType>>
{
public:
AggregateFunctionUniqCombined(const DataTypes & argument_types_, const Array & params_)
: IAggregateFunctionDataHelper<AggregateFunctionUniqCombinedData<T, K, HashValueType>, AggregateFunctionUniqCombined<T, K, HashValueType>>(argument_types_, params_) {}
String getName() const override
{
if constexpr (std::is_same_v<HashValueType, UInt64>)
return "uniqCombined64";
else
return "uniqCombined";
}
DataTypePtr getReturnType() const override
{
return std::make_shared<DataTypeUInt64>();
}
bool allocatesMemoryInArena() const override { return false; }
void add(AggregateDataPtr __restrict place, const IColumn ** columns, size_t row_num, Arena *) const override
{
if constexpr (!std::is_same_v<T, String>)
{
const auto & value = assert_cast<const ColumnVector<T> &>(*columns[0]).getElement(row_num);
this->data(place).set.insert(detail::AggregateFunctionUniqCombinedTraits<T, HashValueType>::hash(value));
}
else
{
StringRef value = columns[0]->getDataAt(row_num);
this->data(place).set.insert(CityHash_v1_0_2::CityHash64(value.data, value.size));
}
}
void merge(AggregateDataPtr __restrict place, ConstAggregateDataPtr rhs, Arena *) const override
{
this->data(place).set.merge(this->data(rhs).set);
}
void serialize(ConstAggregateDataPtr __restrict place, WriteBuffer & buf) const override
{
this->data(place).set.write(buf);
}
void deserialize(AggregateDataPtr __restrict place, ReadBuffer & buf, Arena *) const override
{
this->data(place).set.read(buf);
}
void insertResultInto(AggregateDataPtr __restrict place, IColumn & to, Arena *) const override
{
assert_cast<ColumnUInt64 &>(to).getData().push_back(this->data(place).set.size());
}
};
/** For multiple arguments. To compute, hashes them.
* You can pass multiple arguments as is; You can also pass one argument - a tuple.
* But (for the possibility of efficient implementation), you can not pass several arguments, among which there are tuples.
*/
template <bool is_exact, bool argument_is_tuple, UInt8 K, typename HashValueType>
class AggregateFunctionUniqCombinedVariadic final : public IAggregateFunctionDataHelper<AggregateFunctionUniqCombinedData<UInt64, K, HashValueType>,
AggregateFunctionUniqCombinedVariadic<is_exact, argument_is_tuple, K, HashValueType>>
{
private:
size_t num_args = 0;
public:
explicit AggregateFunctionUniqCombinedVariadic(const DataTypes & arguments, const Array & params)
: IAggregateFunctionDataHelper<AggregateFunctionUniqCombinedData<UInt64, K, HashValueType>,
AggregateFunctionUniqCombinedVariadic<is_exact, argument_is_tuple, K, HashValueType>>(arguments, params)
{
if (argument_is_tuple)
num_args = typeid_cast<const DataTypeTuple &>(*arguments[0]).getElements().size();
else
num_args = arguments.size();
}
String getName() const override
{
if constexpr (std::is_same_v<HashValueType, UInt64>)
return "uniqCombined64";
else
return "uniqCombined";
}
DataTypePtr getReturnType() const override
{
return std::make_shared<DataTypeUInt64>();
}
bool allocatesMemoryInArena() const override { return false; }
void add(AggregateDataPtr __restrict place, const IColumn ** columns, size_t row_num, Arena *) const override
{
this->data(place).set.insert(typename AggregateFunctionUniqCombinedData<UInt64, K, HashValueType>::Set::value_type(
UniqVariadicHash<is_exact, argument_is_tuple>::apply(num_args, columns, row_num)));
}
void merge(AggregateDataPtr __restrict place, ConstAggregateDataPtr rhs, Arena *) const override
{
this->data(place).set.merge(this->data(rhs).set);
}
void serialize(ConstAggregateDataPtr __restrict place, WriteBuffer & buf) const override
{
this->data(place).set.write(buf);
}
void deserialize(AggregateDataPtr __restrict place, ReadBuffer & buf, Arena *) const override
{
this->data(place).set.read(buf);
}
void insertResultInto(AggregateDataPtr __restrict place, IColumn & to, Arena *) const override
{
assert_cast<ColumnUInt64 &>(to).getData().push_back(this->data(place).set.size());
}
};
}