#include "ComplexKeyHashedDictionary.h"
#include <ext/map.h>
#include <ext/range.h>
#include "DictionaryBlockInputStream.h"
#include "DictionaryFactory.h"

namespace DB
{
namespace ErrorCodes
{
    extern const int TYPE_MISMATCH;
    extern const int ARGUMENT_OUT_OF_BOUND;
    extern const int BAD_ARGUMENTS;
    extern const int DICTIONARY_IS_EMPTY;
}

ComplexKeyHashedDictionary::ComplexKeyHashedDictionary(
    const std::string & name,
    const DictionaryStructure & dict_struct,
    DictionarySourcePtr source_ptr,
    const DictionaryLifetime dict_lifetime,
    bool require_nonempty,
    BlockPtr saved_block)
    : name{name}
    , dict_struct(dict_struct)
    , source_ptr{std::move(source_ptr)}
    , dict_lifetime(dict_lifetime)
    , require_nonempty(require_nonempty)
    , saved_block{std::move(saved_block)}
{
    createAttributes();

    try
    {
        loadData();
        calculateBytesAllocated();
    }
    catch (...)
    {
        creation_exception = std::current_exception();
    }

    creation_time = std::chrono::system_clock::now();
}

ComplexKeyHashedDictionary::ComplexKeyHashedDictionary(const ComplexKeyHashedDictionary & other)
    : ComplexKeyHashedDictionary{
          other.name, other.dict_struct, other.source_ptr->clone(), other.dict_lifetime, other.require_nonempty, other.saved_block}
{
}

#define DECLARE(TYPE) \
    void ComplexKeyHashedDictionary::get##TYPE( \
        const std::string & attribute_name, const Columns & key_columns, const DataTypes & key_types, ResultArrayType<TYPE> & out) const \
    { \
        dict_struct.validateKeyTypes(key_types); \
\
        const auto & attribute = getAttribute(attribute_name); \
        if (!isAttributeTypeConvertibleTo(attribute.type, AttributeUnderlyingType::TYPE)) \
            throw Exception{name + ": type mismatch: attribute " + attribute_name + " has type " + toString(attribute.type), \
                            ErrorCodes::TYPE_MISMATCH}; \
\
        const auto null_value = std::get<TYPE>(attribute.null_values); \
\
        getItemsNumber<TYPE>( \
            attribute, \
            key_columns, \
            [&](const size_t row, const auto value) { out[row] = value; }, \
            [&](const size_t) { return null_value; }); \
    }
DECLARE(UInt8)
DECLARE(UInt16)
DECLARE(UInt32)
DECLARE(UInt64)
DECLARE(UInt128)
DECLARE(Int8)
DECLARE(Int16)
DECLARE(Int32)
DECLARE(Int64)
DECLARE(Float32)
DECLARE(Float64)
DECLARE(Decimal32)
DECLARE(Decimal64)
DECLARE(Decimal128)
#undef DECLARE

void ComplexKeyHashedDictionary::getString(
    const std::string & attribute_name, const Columns & key_columns, const DataTypes & key_types, ColumnString * out) const
{
    dict_struct.validateKeyTypes(key_types);

    const auto & attribute = getAttribute(attribute_name);
    if (!isAttributeTypeConvertibleTo(attribute.type, AttributeUnderlyingType::String))
        throw Exception{name + ": type mismatch: attribute " + attribute_name + " has type " + toString(attribute.type),
                        ErrorCodes::TYPE_MISMATCH};

    const auto & null_value = StringRef{std::get<String>(attribute.null_values)};

    getItemsImpl<StringRef, StringRef>(
        attribute,
        key_columns,
        [&](const size_t, const StringRef value) { out->insertData(value.data, value.size); },
        [&](const size_t) { return null_value; });
}

#define DECLARE(TYPE) \
    void ComplexKeyHashedDictionary::get##TYPE( \
        const std::string & attribute_name, \
        const Columns & key_columns, \
        const DataTypes & key_types, \
        const PaddedPODArray<TYPE> & def, \
        ResultArrayType<TYPE> & out) const \
    { \
        dict_struct.validateKeyTypes(key_types); \
\
        const auto & attribute = getAttribute(attribute_name); \
        if (!isAttributeTypeConvertibleTo(attribute.type, AttributeUnderlyingType::TYPE)) \
            throw Exception{name + ": type mismatch: attribute " + attribute_name + " has type " + toString(attribute.type), \
                            ErrorCodes::TYPE_MISMATCH}; \
\
        getItemsNumber<TYPE>( \
            attribute, \
            key_columns, \
            [&](const size_t row, const auto value) { out[row] = value; }, \
            [&](const size_t row) { return def[row]; }); \
    }
DECLARE(UInt8)
DECLARE(UInt16)
DECLARE(UInt32)
DECLARE(UInt64)
DECLARE(UInt128)
DECLARE(Int8)
DECLARE(Int16)
DECLARE(Int32)
DECLARE(Int64)
DECLARE(Float32)
DECLARE(Float64)
DECLARE(Decimal32)
DECLARE(Decimal64)
DECLARE(Decimal128)
#undef DECLARE

void ComplexKeyHashedDictionary::getString(
    const std::string & attribute_name,
    const Columns & key_columns,
    const DataTypes & key_types,
    const ColumnString * const def,
    ColumnString * const out) const
{
    dict_struct.validateKeyTypes(key_types);

    const auto & attribute = getAttribute(attribute_name);
    if (!isAttributeTypeConvertibleTo(attribute.type, AttributeUnderlyingType::String))
        throw Exception{name + ": type mismatch: attribute " + attribute_name + " has type " + toString(attribute.type),
                        ErrorCodes::TYPE_MISMATCH};

    getItemsImpl<StringRef, StringRef>(
        attribute,
        key_columns,
        [&](const size_t, const StringRef value) { out->insertData(value.data, value.size); },
        [&](const size_t row) { return def->getDataAt(row); });
}

#define DECLARE(TYPE) \
    void ComplexKeyHashedDictionary::get##TYPE( \
        const std::string & attribute_name, \
        const Columns & key_columns, \
        const DataTypes & key_types, \
        const TYPE def, \
        ResultArrayType<TYPE> & out) const \
    { \
        dict_struct.validateKeyTypes(key_types); \
\
        const auto & attribute = getAttribute(attribute_name); \
        if (!isAttributeTypeConvertibleTo(attribute.type, AttributeUnderlyingType::TYPE)) \
            throw Exception{name + ": type mismatch: attribute " + attribute_name + " has type " + toString(attribute.type), \
                            ErrorCodes::TYPE_MISMATCH}; \
\
        getItemsNumber<TYPE>( \
            attribute, key_columns, [&](const size_t row, const auto value) { out[row] = value; }, [&](const size_t) { return def; }); \
    }
DECLARE(UInt8)
DECLARE(UInt16)
DECLARE(UInt32)
DECLARE(UInt64)
DECLARE(UInt128)
DECLARE(Int8)
DECLARE(Int16)
DECLARE(Int32)
DECLARE(Int64)
DECLARE(Float32)
DECLARE(Float64)
DECLARE(Decimal32)
DECLARE(Decimal64)
DECLARE(Decimal128)
#undef DECLARE

void ComplexKeyHashedDictionary::getString(
    const std::string & attribute_name,
    const Columns & key_columns,
    const DataTypes & key_types,
    const String & def,
    ColumnString * const out) const
{
    dict_struct.validateKeyTypes(key_types);

    const auto & attribute = getAttribute(attribute_name);
    if (!isAttributeTypeConvertibleTo(attribute.type, AttributeUnderlyingType::String))
        throw Exception{name + ": type mismatch: attribute " + attribute_name + " has type " + toString(attribute.type),
                        ErrorCodes::TYPE_MISMATCH};

    getItemsImpl<StringRef, StringRef>(
        attribute,
        key_columns,
        [&](const size_t, const StringRef value) { out->insertData(value.data, value.size); },
        [&](const size_t) { return StringRef{def}; });
}

void ComplexKeyHashedDictionary::has(const Columns & key_columns, const DataTypes & key_types, PaddedPODArray<UInt8> & out) const
{
    dict_struct.validateKeyTypes(key_types);

    const auto & attribute = attributes.front();

    switch (attribute.type)
    {
        case AttributeUnderlyingType::UInt8:
            has<UInt8>(attribute, key_columns, out);
            break;
        case AttributeUnderlyingType::UInt16:
            has<UInt16>(attribute, key_columns, out);
            break;
        case AttributeUnderlyingType::UInt32:
            has<UInt32>(attribute, key_columns, out);
            break;
        case AttributeUnderlyingType::UInt64:
            has<UInt64>(attribute, key_columns, out);
            break;
        case AttributeUnderlyingType::UInt128:
            has<UInt128>(attribute, key_columns, out);
            break;
        case AttributeUnderlyingType::Int8:
            has<Int8>(attribute, key_columns, out);
            break;
        case AttributeUnderlyingType::Int16:
            has<Int16>(attribute, key_columns, out);
            break;
        case AttributeUnderlyingType::Int32:
            has<Int32>(attribute, key_columns, out);
            break;
        case AttributeUnderlyingType::Int64:
            has<Int64>(attribute, key_columns, out);
            break;
        case AttributeUnderlyingType::Float32:
            has<Float32>(attribute, key_columns, out);
            break;
        case AttributeUnderlyingType::Float64:
            has<Float64>(attribute, key_columns, out);
            break;
        case AttributeUnderlyingType::String:
            has<StringRef>(attribute, key_columns, out);
            break;

        case AttributeUnderlyingType::Decimal32:
            has<Decimal32>(attribute, key_columns, out);
            break;
        case AttributeUnderlyingType::Decimal64:
            has<Decimal64>(attribute, key_columns, out);
            break;
        case AttributeUnderlyingType::Decimal128:
            has<Decimal128>(attribute, key_columns, out);
            break;
    }
}

void ComplexKeyHashedDictionary::createAttributes()
{
    const auto size = dict_struct.attributes.size();
    attributes.reserve(size);

    for (const auto & attribute : dict_struct.attributes)
    {
        attribute_index_by_name.emplace(attribute.name, attributes.size());
        attributes.push_back(createAttributeWithType(attribute.underlying_type, attribute.null_value));

        if (attribute.hierarchical)
            throw Exception{name + ": hierarchical attributes not supported for dictionary of type " + getTypeName(),
                            ErrorCodes::TYPE_MISMATCH};
    }
}

void ComplexKeyHashedDictionary::blockToAttributes(const Block & block)
{
    /// created upfront to avoid excess allocations
    const auto keys_size = dict_struct.key->size();
    StringRefs keys(keys_size);

    const auto attributes_size = attributes.size();
    const auto rows = block.rows();
    element_count += rows;

    const auto key_column_ptrs = ext::map<Columns>(
        ext::range(0, keys_size), [&](const size_t attribute_idx) { return block.safeGetByPosition(attribute_idx).column; });

    const auto attribute_column_ptrs = ext::map<Columns>(ext::range(0, attributes_size), [&](const size_t attribute_idx)
    {
        return block.safeGetByPosition(keys_size + attribute_idx).column;
    });

    for (const auto row_idx : ext::range(0, rows))
    {
        /// calculate key once per row
        const auto key = placeKeysInPool(row_idx, key_column_ptrs, keys, keys_pool);

        auto should_rollback = false;

        for (const auto attribute_idx : ext::range(0, attributes_size))
        {
            const auto & attribute_column = *attribute_column_ptrs[attribute_idx];
            auto & attribute = attributes[attribute_idx];
            const auto inserted = setAttributeValue(attribute, key, attribute_column[row_idx]);
            if (!inserted)
                should_rollback = true;
        }

        /// @note on multiple equal keys the mapped value for the first one is stored
        if (should_rollback)
            keys_pool.rollback(key.size);
    }
}

void ComplexKeyHashedDictionary::updateData()
{
    /// created upfront to avoid excess allocations
    const auto keys_size = dict_struct.key->size();
    StringRefs keys(keys_size);

    const auto attributes_size = attributes.size();

    if (!saved_block || saved_block->rows() == 0)
    {
        auto stream = source_ptr->loadUpdatedAll();
        stream->readPrefix();

        while (const auto block = stream->read())
        {
            /// We are using this method to keep saved data if input stream consists of multiple blocks
            if (!saved_block)
                saved_block = std::make_shared<DB::Block>(block.cloneEmpty());
            for (const auto attribute_idx : ext::range(0, keys_size + attributes_size))
            {
                const IColumn & update_column = *block.getByPosition(attribute_idx).column.get();
                MutableColumnPtr saved_column = saved_block->getByPosition(attribute_idx).column->assumeMutable();
                saved_column->insertRangeFrom(update_column, 0, update_column.size());
            }
        }
        stream->readSuffix();
    }
    else
    {
        auto stream = source_ptr->loadUpdatedAll();

        stream->readPrefix();
        while (Block block = stream->read())
        {
            const auto saved_key_column_ptrs = ext::map<Columns>(
                ext::range(0, keys_size), [&](const size_t key_idx) { return saved_block->safeGetByPosition(key_idx).column; });

            const auto update_key_column_ptrs = ext::map<Columns>(
                ext::range(0, keys_size), [&](const size_t key_idx) { return block.safeGetByPosition(key_idx).column; });

            Arena temp_key_pool;
            ContainerType<std::vector<size_t>> update_key_hash;

            for (size_t i = 0; i < block.rows(); ++i)
            {
                const auto u_key = placeKeysInPool(i, update_key_column_ptrs, keys, temp_key_pool);
                update_key_hash[u_key].push_back(i);
            }

            const size_t rows = saved_block->rows();
            IColumn::Filter filter(rows);

            for (size_t i = 0; i < saved_block->rows(); ++i)
            {
                const auto s_key = placeKeysInPool(i, saved_key_column_ptrs, keys, temp_key_pool);
                auto it = update_key_hash.find(s_key);
                if (it != std::end(update_key_hash))
                    filter[i] = 0;
                else
                    filter[i] = 1;
            }

            auto block_columns = block.mutateColumns();
            for (const auto attribute_idx : ext::range(0, keys_size + attributes_size))
            {
                auto & column = saved_block->safeGetByPosition(attribute_idx).column;
                const auto & filtered_column = column->filter(filter, -1);

                block_columns[attribute_idx]->insertRangeFrom(*filtered_column.get(), 0, filtered_column->size());
            }

            saved_block->setColumns(std::move(block_columns));
        }
        stream->readSuffix();
    }

    if (saved_block)
        blockToAttributes(*saved_block.get());
}

void ComplexKeyHashedDictionary::loadData()
{
    if (!source_ptr->hasUpdateField())
    {
        auto stream = source_ptr->loadAll();
        stream->readPrefix();

        while (const auto block = stream->read())
            blockToAttributes(block);

        stream->readSuffix();
    }
    else
        updateData();

    if (require_nonempty && 0 == element_count)
        throw Exception{name + ": dictionary source is empty and 'require_nonempty' property is set.", ErrorCodes::DICTIONARY_IS_EMPTY};
}

template <typename T>
void ComplexKeyHashedDictionary::addAttributeSize(const Attribute & attribute)
{
    const auto & map_ref = std::get<ContainerType<T>>(attribute.maps);
    bytes_allocated += sizeof(ContainerType<T>) + map_ref.getBufferSizeInBytes();
    bucket_count = map_ref.getBufferSizeInCells();
}

void ComplexKeyHashedDictionary::calculateBytesAllocated()
{
    bytes_allocated += attributes.size() * sizeof(attributes.front());

    for (const auto & attribute : attributes)
    {
        switch (attribute.type)
        {
            case AttributeUnderlyingType::UInt8:
                addAttributeSize<UInt8>(attribute);
                break;
            case AttributeUnderlyingType::UInt16:
                addAttributeSize<UInt16>(attribute);
                break;
            case AttributeUnderlyingType::UInt32:
                addAttributeSize<UInt32>(attribute);
                break;
            case AttributeUnderlyingType::UInt64:
                addAttributeSize<UInt64>(attribute);
                break;
            case AttributeUnderlyingType::UInt128:
                addAttributeSize<UInt128>(attribute);
                break;
            case AttributeUnderlyingType::Int8:
                addAttributeSize<Int8>(attribute);
                break;
            case AttributeUnderlyingType::Int16:
                addAttributeSize<Int16>(attribute);
                break;
            case AttributeUnderlyingType::Int32:
                addAttributeSize<Int32>(attribute);
                break;
            case AttributeUnderlyingType::Int64:
                addAttributeSize<Int64>(attribute);
                break;
            case AttributeUnderlyingType::Float32:
                addAttributeSize<Float32>(attribute);
                break;
            case AttributeUnderlyingType::Float64:
                addAttributeSize<Float64>(attribute);
                break;

            case AttributeUnderlyingType::Decimal32:
                addAttributeSize<Decimal32>(attribute);
                break;
            case AttributeUnderlyingType::Decimal64:
                addAttributeSize<Decimal64>(attribute);
                break;
            case AttributeUnderlyingType::Decimal128:
                addAttributeSize<Decimal128>(attribute);
                break;

            case AttributeUnderlyingType::String:
            {
                addAttributeSize<StringRef>(attribute);
                bytes_allocated += sizeof(Arena) + attribute.string_arena->size();

                break;
            }
        }
    }

    bytes_allocated += keys_pool.size();
}

template <typename T>
void ComplexKeyHashedDictionary::createAttributeImpl(Attribute & attribute, const Field & null_value)
{
    attribute.null_values = T(null_value.get<NearestFieldType<T>>());
    attribute.maps.emplace<ContainerType<T>>();
}

ComplexKeyHashedDictionary::Attribute
ComplexKeyHashedDictionary::createAttributeWithType(const AttributeUnderlyingType type, const Field & null_value)
{
    Attribute attr{type, {}, {}, {}};

    switch (type)
    {
        case AttributeUnderlyingType::UInt8:
            createAttributeImpl<UInt8>(attr, null_value);
            break;
        case AttributeUnderlyingType::UInt16:
            createAttributeImpl<UInt16>(attr, null_value);
            break;
        case AttributeUnderlyingType::UInt32:
            createAttributeImpl<UInt32>(attr, null_value);
            break;
        case AttributeUnderlyingType::UInt64:
            createAttributeImpl<UInt64>(attr, null_value);
            break;
        case AttributeUnderlyingType::UInt128:
            createAttributeImpl<UInt128>(attr, null_value);
            break;
        case AttributeUnderlyingType::Int8:
            createAttributeImpl<Int8>(attr, null_value);
            break;
        case AttributeUnderlyingType::Int16:
            createAttributeImpl<Int16>(attr, null_value);
            break;
        case AttributeUnderlyingType::Int32:
            createAttributeImpl<Int32>(attr, null_value);
            break;
        case AttributeUnderlyingType::Int64:
            createAttributeImpl<Int64>(attr, null_value);
            break;
        case AttributeUnderlyingType::Float32:
            createAttributeImpl<Float32>(attr, null_value);
            break;
        case AttributeUnderlyingType::Float64:
            createAttributeImpl<Float64>(attr, null_value);
            break;

        case AttributeUnderlyingType::Decimal32:
            createAttributeImpl<Decimal32>(attr, null_value);
            break;
        case AttributeUnderlyingType::Decimal64:
            createAttributeImpl<Decimal64>(attr, null_value);
            break;
        case AttributeUnderlyingType::Decimal128:
            createAttributeImpl<Decimal128>(attr, null_value);
            break;

        case AttributeUnderlyingType::String:
        {
            attr.null_values = null_value.get<String>();
            attr.maps.emplace<ContainerType<StringRef>>();
            attr.string_arena = std::make_unique<Arena>();
            break;
        }
    }

    return attr;
}


template <typename OutputType, typename ValueSetter, typename DefaultGetter>
void ComplexKeyHashedDictionary::getItemsNumber(
    const Attribute & attribute, const Columns & key_columns, ValueSetter && set_value, DefaultGetter && get_default) const
{
    if (false)
    {
    }
#define DISPATCH(TYPE) \
    else if (attribute.type == AttributeUnderlyingType::TYPE) getItemsImpl<TYPE, OutputType>( \
        attribute, key_columns, std::forward<ValueSetter>(set_value), std::forward<DefaultGetter>(get_default));
    DISPATCH(UInt8)
    DISPATCH(UInt16)
    DISPATCH(UInt32)
    DISPATCH(UInt64)
    DISPATCH(UInt128)
    DISPATCH(Int8)
    DISPATCH(Int16)
    DISPATCH(Int32)
    DISPATCH(Int64)
    DISPATCH(Float32)
    DISPATCH(Float64)
    DISPATCH(Decimal32)
    DISPATCH(Decimal64)
    DISPATCH(Decimal128)
#undef DISPATCH
    else throw Exception("Unexpected type of attribute: " + toString(attribute.type), ErrorCodes::LOGICAL_ERROR);
}

template <typename AttributeType, typename OutputType, typename ValueSetter, typename DefaultGetter>
void ComplexKeyHashedDictionary::getItemsImpl(
    const Attribute & attribute, const Columns & key_columns, ValueSetter && set_value, DefaultGetter && get_default) const
{
    const auto & attr = std::get<ContainerType<AttributeType>>(attribute.maps);

    const auto keys_size = key_columns.size();
    StringRefs keys(keys_size);
    Arena temporary_keys_pool;

    const auto rows = key_columns.front()->size();
    for (const auto i : ext::range(0, rows))
    {
        /// copy key data to arena so it is contiguous and return StringRef to it
        const auto key = placeKeysInPool(i, key_columns, keys, temporary_keys_pool);

        const auto it = attr.find(key);
        set_value(i, it != attr.end() ? static_cast<OutputType>(it->second) : get_default(i));

        /// free memory allocated for the key
        temporary_keys_pool.rollback(key.size);
    }

    query_count.fetch_add(rows, std::memory_order_relaxed);
}


template <typename T>
bool ComplexKeyHashedDictionary::setAttributeValueImpl(Attribute & attribute, const StringRef key, const T value)
{
    auto & map = std::get<ContainerType<T>>(attribute.maps);
    const auto pair = map.insert({key, value});
    return pair.second;
}

bool ComplexKeyHashedDictionary::setAttributeValue(Attribute & attribute, const StringRef key, const Field & value)
{
    switch (attribute.type)
    {
        case AttributeUnderlyingType::UInt8:
            return setAttributeValueImpl<UInt8>(attribute, key, value.get<UInt64>());
        case AttributeUnderlyingType::UInt16:
            return setAttributeValueImpl<UInt16>(attribute, key, value.get<UInt64>());
        case AttributeUnderlyingType::UInt32:
            return setAttributeValueImpl<UInt32>(attribute, key, value.get<UInt64>());
        case AttributeUnderlyingType::UInt64:
            return setAttributeValueImpl<UInt64>(attribute, key, value.get<UInt64>());
        case AttributeUnderlyingType::UInt128:
            return setAttributeValueImpl<UInt128>(attribute, key, value.get<UInt128>());
        case AttributeUnderlyingType::Int8:
            return setAttributeValueImpl<Int8>(attribute, key, value.get<Int64>());
        case AttributeUnderlyingType::Int16:
            return setAttributeValueImpl<Int16>(attribute, key, value.get<Int64>());
        case AttributeUnderlyingType::Int32:
            return setAttributeValueImpl<Int32>(attribute, key, value.get<Int64>());
        case AttributeUnderlyingType::Int64:
            return setAttributeValueImpl<Int64>(attribute, key, value.get<Int64>());
        case AttributeUnderlyingType::Float32:
            return setAttributeValueImpl<Float32>(attribute, key, value.get<Float64>());
        case AttributeUnderlyingType::Float64:
            return setAttributeValueImpl<Float64>(attribute, key, value.get<Float64>());

        case AttributeUnderlyingType::Decimal32:
            return setAttributeValueImpl<Decimal32>(attribute, key, value.get<Decimal32>());
        case AttributeUnderlyingType::Decimal64:
            return setAttributeValueImpl<Decimal64>(attribute, key, value.get<Decimal64>());
        case AttributeUnderlyingType::Decimal128:
            return setAttributeValueImpl<Decimal128>(attribute, key, value.get<Decimal128>());

        case AttributeUnderlyingType::String:
        {
            auto & map = std::get<ContainerType<StringRef>>(attribute.maps);
            const auto & string = value.get<String>();
            const auto string_in_arena = attribute.string_arena->insert(string.data(), string.size());
            const auto pair = map.insert({key, StringRef{string_in_arena, string.size()}});
            return pair.second;
        }
    }

    return {};
}

const ComplexKeyHashedDictionary::Attribute & ComplexKeyHashedDictionary::getAttribute(const std::string & attribute_name) const
{
    const auto it = attribute_index_by_name.find(attribute_name);
    if (it == std::end(attribute_index_by_name))
        throw Exception{name + ": no such attribute '" + attribute_name + "'", ErrorCodes::BAD_ARGUMENTS};

    return attributes[it->second];
}

StringRef ComplexKeyHashedDictionary::placeKeysInPool(const size_t row, const Columns & key_columns, StringRefs & keys, Arena & pool)
{
    const auto keys_size = key_columns.size();
    size_t sum_keys_size{};

    const char * block_start = nullptr;
    for (size_t j = 0; j < keys_size; ++j)
    {
        keys[j] = key_columns[j]->serializeValueIntoArena(row, pool, block_start);
        sum_keys_size += keys[j].size;
    }

    auto key_start = block_start;
    for (size_t j = 0; j < keys_size; ++j)
    {
        keys[j].data = key_start;
        key_start += keys[j].size;
    }

    return {block_start, sum_keys_size};
}

template <typename T>
void ComplexKeyHashedDictionary::has(const Attribute & attribute, const Columns & key_columns, PaddedPODArray<UInt8> & out) const
{
    const auto & attr = std::get<ContainerType<T>>(attribute.maps);
    const auto keys_size = key_columns.size();
    StringRefs keys(keys_size);
    Arena temporary_keys_pool;
    const auto rows = key_columns.front()->size();

    for (const auto i : ext::range(0, rows))
    {
        /// copy key data to arena so it is contiguous and return StringRef to it
        const auto key = placeKeysInPool(i, key_columns, keys, temporary_keys_pool);

        const auto it = attr.find(key);
        out[i] = it != attr.end();

        /// free memory allocated for the key
        temporary_keys_pool.rollback(key.size);
    }

    query_count.fetch_add(rows, std::memory_order_relaxed);
}

std::vector<StringRef> ComplexKeyHashedDictionary::getKeys() const
{
    const Attribute & attribute = attributes.front();

    switch (attribute.type)
    {
        case AttributeUnderlyingType::UInt8:
            return getKeys<UInt8>(attribute);
        case AttributeUnderlyingType::UInt16:
            return getKeys<UInt16>(attribute);
        case AttributeUnderlyingType::UInt32:
            return getKeys<UInt32>(attribute);
        case AttributeUnderlyingType::UInt64:
            return getKeys<UInt64>(attribute);
        case AttributeUnderlyingType::UInt128:
            return getKeys<UInt128>(attribute);
        case AttributeUnderlyingType::Int8:
            return getKeys<Int8>(attribute);
        case AttributeUnderlyingType::Int16:
            return getKeys<Int16>(attribute);
        case AttributeUnderlyingType::Int32:
            return getKeys<Int32>(attribute);
        case AttributeUnderlyingType::Int64:
            return getKeys<Int64>(attribute);
        case AttributeUnderlyingType::Float32:
            return getKeys<Float32>(attribute);
        case AttributeUnderlyingType::Float64:
            return getKeys<Float64>(attribute);
        case AttributeUnderlyingType::String:
            return getKeys<StringRef>(attribute);

        case AttributeUnderlyingType::Decimal32:
            return getKeys<Decimal32>(attribute);
        case AttributeUnderlyingType::Decimal64:
            return getKeys<Decimal64>(attribute);
        case AttributeUnderlyingType::Decimal128:
            return getKeys<Decimal128>(attribute);
    }
    return {};
}

template <typename T>
std::vector<StringRef> ComplexKeyHashedDictionary::getKeys(const Attribute & attribute) const
{
    const ContainerType<T> & attr = std::get<ContainerType<T>>(attribute.maps);
    std::vector<StringRef> keys;
    keys.reserve(attr.size());
    for (const auto & key : attr)
        keys.push_back(key.first);

    return keys;
}

BlockInputStreamPtr ComplexKeyHashedDictionary::getBlockInputStream(const Names & column_names, size_t max_block_size) const
{
    using BlockInputStreamType = DictionaryBlockInputStream<ComplexKeyHashedDictionary, UInt64>;
    return std::make_shared<BlockInputStreamType>(shared_from_this(), max_block_size, getKeys(), column_names);
}

void registerDictionaryComplexKeyHashed(DictionaryFactory & factory)
{
    auto create_layout = [=](const std::string & name,
                             const DictionaryStructure & dict_struct,
                             const Poco::Util::AbstractConfiguration & config,
                             const std::string & config_prefix,
                             DictionarySourcePtr source_ptr) -> DictionaryPtr
    {
        if (!dict_struct.key)
            throw Exception{"'key' is required for dictionary of layout 'complex_key_hashed'", ErrorCodes::BAD_ARGUMENTS};

        const DictionaryLifetime dict_lifetime{config, config_prefix + ".lifetime"};
        const bool require_nonempty = config.getBool(config_prefix + ".require_nonempty", false);
        return std::make_unique<ComplexKeyHashedDictionary>(name, dict_struct, std::move(source_ptr), dict_lifetime, require_nonempty);
    };
    factory.registerLayout("complex_key_hashed", create_layout);
}


}