ClickHouse/dbms/include/DB/Dictionaries/RangeHashedDictionary.h

#pragma once

#include <DB/Dictionaries/IDictionary.h>
#include <DB/Dictionaries/IDictionarySource.h>
#include <DB/Dictionaries/DictionaryStructure.h>
#include <DB/Common/HashTable/HashMap.h>
#include <DB/Columns/ColumnString.h>
#include <ext/range.hpp>
#include <atomic>
#include <memory>
#include <tuple>


namespace DB
{

class RangeHashedDictionary final : public IDictionaryBase
{
public:
	RangeHashedDictionary(
		const std::string & name, const DictionaryStructure & dict_struct, DictionarySourcePtr source_ptr,
		const DictionaryLifetime dict_lifetime, bool require_nonempty);

	RangeHashedDictionary(const RangeHashedDictionary & other);

	std::exception_ptr getCreationException() const override { return creation_exception; }

	std::string getName() const override { return name; }

	std::string getTypeName() const override { return "RangeHashed"; }

	std::size_t getBytesAllocated() const override { return bytes_allocated; }

	std::size_t getQueryCount() const override { return query_count.load(std::memory_order_relaxed); }

	double getHitRate() const override { return 1.0; }

	std::size_t getElementCount() const override { return element_count; }

	double getLoadFactor() const override { return static_cast<double>(element_count) / bucket_count; }

	bool isCached() const override { return false; }

	DictionaryPtr clone() const override { return std::make_unique<RangeHashedDictionary>(*this); }

	const IDictionarySource * getSource() const override { return source_ptr.get(); }

	const DictionaryLifetime & getLifetime() const override { return dict_lifetime; }

	const DictionaryStructure & getStructure() const override { return dict_struct; }

	std::chrono::time_point<std::chrono::system_clock> getCreationTime() const override
	{
		return creation_time;
	}

	bool isInjective(const std::string & attribute_name) const override
	{
		return dict_struct.attributes[&getAttribute(attribute_name) - attributes.data()].injective;
	}

#define DECLARE_MULTIPLE_GETTER(TYPE)\
	void get##TYPE(\
		const std::string & attribute_name, const PaddedPODArray<Key> & ids, const PaddedPODArray<UInt16> & dates,\
		PaddedPODArray<TYPE> & out) const;
	DECLARE_MULTIPLE_GETTER(UInt8)
	DECLARE_MULTIPLE_GETTER(UInt16)
	DECLARE_MULTIPLE_GETTER(UInt32)
	DECLARE_MULTIPLE_GETTER(UInt64)
	DECLARE_MULTIPLE_GETTER(Int8)
	DECLARE_MULTIPLE_GETTER(Int16)
	DECLARE_MULTIPLE_GETTER(Int32)
	DECLARE_MULTIPLE_GETTER(Int64)
	DECLARE_MULTIPLE_GETTER(Float32)
	DECLARE_MULTIPLE_GETTER(Float64)
#undef DECLARE_MULTIPLE_GETTER

	void getString(
		const std::string & attribute_name, const PaddedPODArray<Key> & ids, const PaddedPODArray<UInt16> & dates,
		ColumnString * out) const;

private:
	struct Range : std::pair<UInt16, UInt16>
	{
		using std::pair<UInt16, UInt16>::pair;

		bool contains(const UInt16 date) const
		{
			const auto & left = first;
			const auto & right = second;

			if (left <= date && date <= right)
				return true;

			const auto has_left_bound = 0 < left && left <= DATE_LUT_MAX_DAY_NUM;
			const auto has_right_bound = 0 < right && right <= DATE_LUT_MAX_DAY_NUM;

			if ((!has_left_bound || left <= date) && (!has_right_bound || date <= right))
				return true;

			return false;
		}
	};

	template <typename T>
	struct Value final
	{
		Range range;
		T value;
	};

	template <typename T> using Values = std::vector<Value<T>>;
	template <typename T> using Collection = HashMap<UInt64, Values<T>>;
	template <typename T> using Ptr = std::unique_ptr<Collection<T>>;

	struct Attribute final
	{
	public:
		AttributeUnderlyingType type;
		std::tuple<UInt8, UInt16, UInt32, UInt64,
				   Int8, Int16, Int32, Int64,
				   Float32, Float64,
				   String> null_values;
		std::tuple<Ptr<UInt8>, Ptr<UInt16>, Ptr<UInt32>, Ptr<UInt64>,
				   Ptr<Int8>, Ptr<Int16>, Ptr<Int32>, Ptr<Int64>,
				   Ptr<Float32>, Ptr<Float64>, Ptr<StringRef>> maps;
		std::unique_ptr<Arena> string_arena;
	};

	void createAttributes();

	void loadData();

	template <typename T>
	void addAttributeSize(const Attribute & attribute);

	void calculateBytesAllocated();

	template <typename T>
	void createAttributeImpl(Attribute & attribute, const Field & null_value);

	Attribute createAttributeWithType(const AttributeUnderlyingType type, const Field & null_value);


	template <typename OutputType>
	void getItems(
		const Attribute & attribute,
		const PaddedPODArray<Key> & ids,
		const PaddedPODArray<UInt16> & dates,
		PaddedPODArray<OutputType> & out) const;

	template <typename AttributeType, typename OutputType>
	void getItemsImpl(
		const Attribute & attribute,
		const PaddedPODArray<Key> & ids,
		const PaddedPODArray<UInt16> & dates,
		PaddedPODArray<OutputType> & out) const;


	template <typename T>
	void setAttributeValueImpl(Attribute & attribute, const Key id, const Range & range, const T value);

	void setAttributeValue(Attribute & attribute, const Key id, const Range & range, const Field & value);

	const Attribute & getAttribute(const std::string & attribute_name) const;

	const Attribute & getAttributeWithType(const std::string & name, const AttributeUnderlyingType type) const;

	const std::string name;
	const DictionaryStructure dict_struct;
	const DictionarySourcePtr source_ptr;
	const DictionaryLifetime dict_lifetime;
	const bool require_nonempty;

	std::map<std::string, std::size_t> attribute_index_by_name;
	std::vector<Attribute> attributes;

	std::size_t bytes_allocated = 0;
	std::size_t element_count = 0;
	std::size_t bucket_count = 0;
	mutable std::atomic<std::size_t> query_count{0};

	std::chrono::time_point<std::chrono::system_clock> creation_time;

	std::exception_ptr creation_exception;
};

}