ClickHouse/dbms/include/DB/AggregateFunctions/AggregateFunctionUniq.h
2015-08-31 18:32:01 +03:00

303 lines
7.7 KiB
C++
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

#pragma once
#include <city.h>
#include <type_traits>
#include <stats/UniquesHashSet.h>
#include <DB/IO/WriteHelpers.h>
#include <DB/IO/ReadHelpers.h>
#include <DB/IO/WriteBufferFromString.h>
#include <DB/DataTypes/DataTypesNumberFixed.h>
#include <DB/DataTypes/DataTypeString.h>
#include <DB/Interpreters/AggregationCommon.h>
#include <DB/Common/HashTable/HashSet.h>
#include <DB/Common/HyperLogLogWithSmallSetOptimization.h>
#include <DB/Common/CombinedCardinalityEstimator.h>
#include <DB/Columns/ColumnString.h>
#include <DB/AggregateFunctions/IUnaryAggregateFunction.h>
#include <DB/AggregateFunctions/UniqCombinedBiasData.h>
namespace DB
{
/// uniq
struct AggregateFunctionUniqUniquesHashSetData
{
typedef UniquesHashSet<DefaultHash<UInt64> > Set;
Set set;
static String getName() { return "uniq"; }
};
/// uniqHLL12
template <typename T>
struct AggregateFunctionUniqHLL12Data
{
typedef HyperLogLogWithSmallSetOptimization<T, 16, 12> Set;
Set set;
static String getName() { return "uniqHLL12"; }
};
template <>
struct AggregateFunctionUniqHLL12Data<String>
{
typedef HyperLogLogWithSmallSetOptimization<UInt64, 16, 12> Set;
Set set;
static String getName() { return "uniqHLL12"; }
};
/// uniqExact
template <typename T>
struct AggregateFunctionUniqExactData
{
typedef T Key;
/// При создании, хэш-таблица должна быть небольшой.
typedef HashSet<
Key,
DefaultHash<Key>,
HashTableGrower<4>,
HashTableAllocatorWithStackMemory<sizeof(Key) * (1 << 4)>
> Set;
Set set;
static String getName() { return "uniqExact"; }
};
/// Для строк будем класть в хэш-таблицу значения SipHash-а (128 бит).
template <>
struct AggregateFunctionUniqExactData<String>
{
typedef UInt128 Key;
/// При создании, хэш-таблица должна быть небольшой.
typedef HashSet<
Key,
UInt128TrivialHash,
HashTableGrower<3>,
HashTableAllocatorWithStackMemory<sizeof(Key) * (1 << 3)>
> Set;
Set set;
static String getName() { return "uniqExact"; }
};
template <typename T, HyperLogLogMode mode>
struct BaseUniqCombinedData
{
using Key = UInt64;
using Set = CombinedCardinalityEstimator<
Key,
HashSet<Key, DefaultHash<Key>, HashTableGrower<> >,
16,
14,
17,
DefaultHash<Key>,
UInt64,
HyperLogLogBiasEstimator<UniqCombinedBiasData>,
mode
>;
Set set;
};
template <HyperLogLogMode mode>
struct BaseUniqCombinedData<String, mode>
{
using Key = UInt64;
using Set = CombinedCardinalityEstimator<
Key,
HashSet<Key, TrivialHash, HashTableGrower<> >,
16,
14,
17,
TrivialHash,
UInt64,
HyperLogLogBiasEstimator<UniqCombinedBiasData>,
mode
>;
Set set;
};
/// Агрегатные функции uniqCombinedRaw, uniqCombinedLinearCounting, и uniqCombinedBiasCorrected
/// предназначены для разработки новых версий функции uniqCombined.
/// Пользователи должны использовать только uniqCombined.
template <typename T>
struct AggregateFunctionUniqCombinedRawData
: public BaseUniqCombinedData<T, HyperLogLogMode::Raw>
{
static String getName() { return "uniqCombinedRaw"; }
};
template <typename T>
struct AggregateFunctionUniqCombinedLinearCountingData
: public BaseUniqCombinedData<T, HyperLogLogMode::LinearCounting>
{
static String getName() { return "uniqCombinedLinearCounting"; }
};
template <typename T>
struct AggregateFunctionUniqCombinedBiasCorrectedData
: public BaseUniqCombinedData<T, HyperLogLogMode::BiasCorrected>
{
static String getName() { return "uniqCombinedBiasCorrected"; }
};
template <typename T>
struct AggregateFunctionUniqCombinedData
: public BaseUniqCombinedData<T, HyperLogLogMode::FullFeatured>
{
static String getName() { return "uniqCombined"; }
};
namespace detail
{
/** Хэш-функция для uniq.
*/
template <typename T> struct AggregateFunctionUniqTraits
{
static UInt64 hash(T x) { return x; }
};
template <> struct AggregateFunctionUniqTraits<Float32>
{
static UInt64 hash(Float32 x)
{
UInt64 res = 0;
memcpy(reinterpret_cast<char *>(&res), reinterpret_cast<char *>(&x), sizeof(x));
return res;
}
};
template <> struct AggregateFunctionUniqTraits<Float64>
{
static UInt64 hash(Float64 x)
{
UInt64 res = 0;
memcpy(reinterpret_cast<char *>(&res), reinterpret_cast<char *>(&x), sizeof(x));
return res;
}
};
/** Структура для делегации работы по добавлению одного элемента в агрегатные функции uniq.
* Используется для частичной специализации для добавления строк.
*/
template <typename T, typename Data, typename Enable = void>
struct OneAdder;
template <typename T, typename Data>
struct OneAdder<T, Data, typename std::enable_if<
std::is_same<Data, AggregateFunctionUniqUniquesHashSetData>::value ||
std::is_same<Data, AggregateFunctionUniqHLL12Data<T> >::value ||
std::is_same<Data, AggregateFunctionUniqCombinedRawData<T> >::value ||
std::is_same<Data, AggregateFunctionUniqCombinedLinearCountingData<T> >::value ||
std::is_same<Data, AggregateFunctionUniqCombinedBiasCorrectedData<T> >::value ||
std::is_same<Data, AggregateFunctionUniqCombinedData<T> >::value>::type>
{
template <typename T2 = T>
static void addOne(Data & data, const IColumn & column, size_t row_num,
typename std::enable_if<!std::is_same<T2, String>::value>::type * = nullptr)
{
const auto & value = static_cast<const ColumnVector<T2> &>(column).getData()[row_num];
data.set.insert(AggregateFunctionUniqTraits<T2>::hash(value));
}
template <typename T2 = T>
static void addOne(Data & data, const IColumn & column, size_t row_num,
typename std::enable_if<std::is_same<T2, String>::value>::type * = nullptr)
{
StringRef value = column.getDataAt(row_num);
data.set.insert(CityHash64(value.data, value.size));
}
};
template <typename T, typename Data>
struct OneAdder<T, Data, typename std::enable_if<
std::is_same<Data, AggregateFunctionUniqExactData<T> >::value>::type>
{
template <typename T2 = T>
static void addOne(Data & data, const IColumn & column, size_t row_num,
typename std::enable_if<!std::is_same<T2, String>::value>::type * = nullptr)
{
data.set.insert(static_cast<const ColumnVector<T2> &>(column).getData()[row_num]);
}
template <typename T2 = T>
static void addOne(Data & data, const IColumn & column, size_t row_num,
typename std::enable_if<std::is_same<T2, String>::value>::type * = nullptr)
{
StringRef value = column.getDataAt(row_num);
UInt128 key;
SipHash hash;
hash.update(value.data, value.size);
hash.get128(key.first, key.second);
data.set.insert(key);
}
};
}
/// Приближённо вычисляет количество различных значений.
template <typename T, typename Data>
class AggregateFunctionUniq final : public IUnaryAggregateFunction<Data, AggregateFunctionUniq<T, Data> >
{
public:
String getName() const { return Data::getName(); }
DataTypePtr getReturnType() const
{
return new DataTypeUInt64;
}
void setArgument(const DataTypePtr & argument)
{
}
void addOne(AggregateDataPtr place, const IColumn & column, size_t row_num) const
{
detail::OneAdder<T, Data>::addOne(this->data(place), column, row_num);
}
void merge(AggregateDataPtr place, ConstAggregateDataPtr rhs) const
{
this->data(place).set.merge(this->data(rhs).set);
}
void serialize(ConstAggregateDataPtr place, WriteBuffer & buf) const
{
this->data(place).set.write(buf);
}
void deserializeMerge(AggregateDataPtr place, ReadBuffer & buf) const
{
this->data(place).set.readAndMerge(buf);
}
void insertResultInto(ConstAggregateDataPtr place, IColumn & to) const
{
static_cast<ColumnUInt64 &>(to).getData().push_back(this->data(place).set.size());
}
};
}