ClickHouse/src/Functions/FunctionsExternalDictionaries.h

#pragma once

#include <DataTypes/DataTypesNumber.h>
#include <DataTypes/DataTypesDecimal.h>
#include <DataTypes/DataTypeArray.h>
#include <DataTypes/DataTypeString.h>
#include <DataTypes/DataTypeDate.h>
#include <DataTypes/DataTypeDateTime.h>
#include <DataTypes/DataTypeTuple.h>
#include <DataTypes/DataTypeUUID.h>
#include <DataTypes/DataTypeNullable.h>
#include <DataTypes/DataTypeLowCardinality.h>

#include <Common/typeid_cast.h>
#include <Common/assert_cast.h>

#include <Columns/ColumnsNumber.h>
#include <Columns/ColumnConst.h>
#include <Columns/ColumnArray.h>
#include <Columns/ColumnString.h>
#include <Columns/ColumnTuple.h>

#include <Access/AccessFlags.h>

#include <Interpreters/Context.h>
#include <Interpreters/ExternalDictionariesLoader.h>
#include <Interpreters/castColumn.h>

#include <Functions/IFunctionImpl.h>
#include <Functions/FunctionHelpers.h>

#include <Dictionaries/FlatDictionary.h>
#include <Dictionaries/HashedDictionary.h>
#include <Dictionaries/CacheDictionary.h>
#include <Dictionaries/ComplexKeyHashedDictionary.h>
#include <Dictionaries/RangeHashedDictionary.h>
#include <Dictionaries/IPAddressDictionary.h>
#include <Dictionaries/PolygonDictionaryImplementations.h>
#include <Dictionaries/DirectDictionary.h>

#include <ext/range.h>

#include <type_traits>

namespace DB
{

namespace ErrorCodes
{
    extern const int ILLEGAL_TYPE_OF_ARGUMENT;
    extern const int UNSUPPORTED_METHOD;
    extern const int UNKNOWN_TYPE;
    extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
    extern const int ILLEGAL_COLUMN;
    extern const int BAD_ARGUMENTS;
    extern const int TYPE_MISMATCH;
}


/** Functions that use plug-ins (external) dictionaries_loader.
  *
  * Get the value of the attribute of the specified type.
  *     dictGetType(dictionary, attribute, id),
  *         Type - placeholder for the type name, any numeric and string types are currently supported.
  *        The type must match the actual attribute type with which it was declared in the dictionary structure.
  *
  * Get an array of identifiers, consisting of the source and parents chain.
  *  dictGetHierarchy(dictionary, id).
  *
  * Is the first identifier the child of the second.
  *  dictIsIn(dictionary, child_id, parent_id).
  */


class FunctionDictHelper
{
public:
    explicit FunctionDictHelper(const Context & context_) : context(context_), external_loader(context.getExternalDictionariesLoader()) {}

    std::shared_ptr<const IDictionaryBase> getDictionary(const String & dictionary_name)
    {
        String resolved_name = DatabaseCatalog::instance().resolveDictionaryName(dictionary_name);

        auto dict = external_loader.tryGetDictionary(resolved_name);

        if (!dict)
        {
            /// If dictionary not found. And database was not implicitly specified
            /// we can qualify dictionary name with current database name.
            /// It will help if dictionary is created with DDL and is in current database.
            if (dictionary_name.find('.') == std::string::npos)
            {
                String dictionary_name_with_database = context.getCurrentDatabase() + '.' + dictionary_name;
                resolved_name = DatabaseCatalog::instance().resolveDictionaryName(dictionary_name_with_database);
                dict = external_loader.tryGetDictionary(resolved_name);
            }
        }

        if (!dict)
            throw Exception(ErrorCodes::BAD_ARGUMENTS, "External dictionary ({}) not found", dictionary_name);

        if (!access_checked)
        {
            context.checkAccess(AccessType::dictGet, dict->getDatabaseOrNoDatabaseTag(), dict->getDictionaryID().getTableName());
            access_checked = true;
        }

        return dict;
    }

    std::shared_ptr<const IDictionaryBase> getDictionary(const ColumnWithTypeAndName & column)
    {
        const auto * dict_name_col = checkAndGetColumnConst<ColumnString>(column.column.get());
        return getDictionary(dict_name_col->getValue<String>());
    }

    bool isDictGetFunctionInjective(const Block & sample_columns)
    {
        /// Assume non-injective by default
        if (!sample_columns)
            return false;

        if (sample_columns.columns() < 3)
            throw Exception{"Wrong arguments count", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH};

        const auto * dict_name_col = checkAndGetColumnConst<ColumnString>(sample_columns.getByPosition(0).column.get());
        if (!dict_name_col)
            throw Exception{"First argument of function dictGet... must be a constant string", ErrorCodes::ILLEGAL_COLUMN};

        const auto * attr_name_col = checkAndGetColumnConst<ColumnString>(sample_columns.getByPosition(1).column.get());
        if (!attr_name_col)
            throw Exception{"Second argument of function dictGet... must be a constant string", ErrorCodes::ILLEGAL_COLUMN};

        return getDictionary(dict_name_col->getValue<String>())->isInjective(attr_name_col->getValue<String>());
    }

    DictionaryStructure getDictionaryStructure(const String & dictionary_name) const
    {
        String resolved_name = DatabaseCatalog::instance().resolveDictionaryName(dictionary_name);

        auto load_result = external_loader.getLoadResult(resolved_name);
        if (!load_result.config)
        {
            /// If dictionary not found. And database was not implicitly specified
            /// we can qualify dictionary name with current database name.
            /// It will help if dictionary is created with DDL and is in current database.
            if (dictionary_name.find('.') == std::string::npos)
            {
                String dictionary_name_with_database = context.getCurrentDatabase() + '.' + dictionary_name;
                resolved_name = DatabaseCatalog::instance().resolveDictionaryName(dictionary_name_with_database);
                load_result = external_loader.getLoadResult(resolved_name);
            }
        }

        if (!load_result.config)
            throw Exception("Dictionary " + backQuote(dictionary_name) + " not found", ErrorCodes::BAD_ARGUMENTS);

        return ExternalDictionariesLoader::getDictionaryStructure(*load_result.config);
    }

    const Context & context;
private:
    const ExternalDictionariesLoader & external_loader;
    /// Access cannot be not granted, since in this case checkAccess() will throw and access_checked will not be updated.
    std::atomic<bool> access_checked = false;

    /// We must not cache dictionary or dictionary's structure here, because there are places
    /// where ExpressionActionsPtr is cached (StorageDistributed caching it for sharding_key_expr and
    /// optimize_skip_unused_shards), and if the dictionary will be cached within "query" then
    /// cached ExpressionActionsPtr will always have first version of the query and the dictionary
    /// will not be updated after reload (see https://github.com/ClickHouse/ClickHouse/pull/16205)
};


class FunctionDictHas final : public IFunction
{
public:
    static constexpr auto name = "dictHas";

    static FunctionPtr create(const Context & context)
    {
        return std::make_shared<FunctionDictHas>(context);
    }

    explicit FunctionDictHas(const Context & context_) : helper(context_) {}

    String getName() const override { return name; }

private:
    size_t getNumberOfArguments() const override { return 0; }
    bool isVariadic() const override { return true; }

    bool isDeterministic() const override { return false; }

    bool useDefaultImplementationForConstants() const final { return true; }

    ColumnNumbers getArgumentsThatAreAlwaysConstant() const final { return {0}; }

    DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
    {
        if (arguments.size() < 2)
            throw Exception{"Wrong argument count for function " + getName(), ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH};

        if (!isString(arguments[0]))
            throw Exception{"Illegal type " + arguments[0]->getName() + " of first argument of function " + getName()
                + ", expected a string.", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};

        if (!WhichDataType(arguments[1]).isUInt64() &&
            !isTuple(arguments[1]))
            throw Exception{"Illegal type " + arguments[1]->getName() + " of second argument of function " + getName()
                + ", must be UInt64 or tuple(...).", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};

        return std::make_shared<DataTypeUInt8>();
    }

    ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const override
    {
        /** Do not require existence of the dictionary if the function is called for empty columns.
          * This is needed to allow successful query analysis on a server,
          *  that is the initiator of a distributed query,
          *  in the case when the function will be invoked for real data only at the remote servers.
          * This feature is controversial and implemented specially
          *  for backward compatibility with the case in Yandex Banner System.
          */
        if (input_rows_count == 0)
            return result_type->createColumn();

        auto dictionary = helper.getDictionary(arguments[0]);
        auto dictionary_key_type = dictionary->getKeyType();

        const ColumnWithTypeAndName & key_column_with_type = arguments[1];
        const auto key_column = key_column_with_type.column;
        const auto key_column_type = WhichDataType(key_column_with_type.type);

        ColumnPtr range_col = nullptr;
        DataTypePtr range_col_type = nullptr;

        if (dictionary_key_type == DictionaryKeyType::range)
        {
            if (arguments.size() != 3)
                throw Exception{"Wrong argument count for function " + getName()
                    + " when dictionary has key type range", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH};

            range_col = arguments[2].column;
            range_col_type = arguments[2].type;

            if (!(range_col_type->isValueRepresentedByInteger() && range_col_type->getSizeOfValueInMemory() <= sizeof(Int64)))
                throw Exception{"Illegal type " + range_col_type->getName() + " of fourth argument of function "
                        + getName() + " must be convertible to Int64.",
                    ErrorCodes::ILLEGAL_COLUMN};
        }

        if (dictionary_key_type == DictionaryKeyType::simple)
        {
            if (!key_column_type.isUInt64())
                throw Exception{"Second argument of function " + getName() + " must be " + dictionary->getStructure().getKeyDescription(),
                    ErrorCodes::TYPE_MISMATCH};

            return dictionary->hasKeys({key_column}, {std::make_shared<DataTypeUInt64>()});
        }
        else if (dictionary_key_type == DictionaryKeyType::complex)
        {
            if (!key_column_type.isTuple())
                throw Exception{"Second argument of function " + getName() + " must be " + dictionary->getStructure().getKeyDescription(),
                    ErrorCodes::TYPE_MISMATCH};

            /// Functions in external dictionaries_loader only support full-value (not constant) columns with keys.
            ColumnPtr key_column_full = key_column->convertToFullColumnIfConst();

            const auto & key_columns = typeid_cast<const ColumnTuple &>(*key_column_full).getColumnsCopy();
            const auto & key_types = static_cast<const DataTypeTuple &>(*key_column_with_type.type).getElements();

            return dictionary->hasKeys(key_columns, key_types);
        }
        else
            return dictionary->hasKeys({key_column, range_col}, {std::make_shared<DataTypeUInt64>(), range_col_type});
    }

    mutable FunctionDictHelper helper;
};

enum class DictionaryGetFunctionType
{
    get,
    getOrDefault
};

/// This variant of function derives the result type automatically.
template <DictionaryGetFunctionType dictionary_get_function_type>
class FunctionDictGetNoType final : public IFunction
{
public:
    static constexpr auto name = dictionary_get_function_type == DictionaryGetFunctionType::get ? "dictGet" : "dictGetOrDefault";

    static FunctionPtr create(const Context & context)
    {
        return std::make_shared<FunctionDictGetNoType>(context);
    }

    explicit FunctionDictGetNoType(const Context & context_) : helper(context_) {}

    String getName() const override { return name; }

    bool isVariadic() const override { return true; }
    size_t getNumberOfArguments() const override { return 0; }

    bool useDefaultImplementationForConstants() const final { return true; }
    ColumnNumbers getArgumentsThatAreAlwaysConstant() const final { return {0, 1}; }

    bool isDeterministic() const override { return false; }

    bool isInjective(const ColumnsWithTypeAndName & sample_columns) const override
    {
        return helper.isDictGetFunctionInjective(sample_columns);
    }

    DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
    {
        if (arguments.size() < 3)
            throw Exception{"Wrong argument count for function " + getName(), ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH};

        String dictionary_name;
        if (const auto * name_col = checkAndGetColumnConst<ColumnString>(arguments[0].column.get()))
            dictionary_name = name_col->getValue<String>();
        else
            throw Exception{"Illegal type " + arguments[0].type->getName() + " of first argument of function " + getName()
                + ", expected a const string.", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};

        Strings attribute_names = getAttributeNamesFromColumn(arguments[1].column, arguments[1].type);

        DataTypes types;

        auto current_database_name = helper.context.getCurrentDatabase();
        auto dictionary_structure = helper.getDictionaryStructure(dictionary_name);

        for (auto & attribute_name : attribute_names)
        {
            /// We're extracting the return type from the dictionary's config, without loading the dictionary.
            auto attribute = dictionary_structure.getAttribute(attribute_name);
            types.emplace_back(attribute.type);
        }

        if (types.size() > 1)
            return std::make_shared<DataTypeTuple>(types);
        else
            return types.front();
    }

    ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const override
    {
        if (input_rows_count == 0)
            return result_type->createColumn();

        String dictionary_name;

        if (const auto * name_col = checkAndGetColumnConst<ColumnString>(arguments[0].column.get()))
            dictionary_name = name_col->getValue<String>();
        else
            throw Exception{"Illegal type " + arguments[0].type->getName() + " of first argument of function " + getName()
                + ", expected a const string.", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};

        Strings attribute_names = getAttributeNamesFromColumn(arguments[1].column, arguments[1].type);

        auto dictionary = helper.getDictionary(dictionary_name);

        if (!WhichDataType(arguments[2].type).isUInt64() && !isTuple(arguments[2].type))
            throw Exception{"Illegal type " + arguments[2].type->getName() + " of third argument of function "
                    + getName() + ", must be UInt64 or tuple(...).",
                ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};

        auto dictionary_key_type = dictionary->getKeyType();

        size_t current_arguments_index = 3;

        ColumnPtr range_col = nullptr;
        DataTypePtr range_col_type = nullptr;

        if (dictionary_key_type == DictionaryKeyType::range)
        {
            if (current_arguments_index >= arguments.size())
                throw Exception{"Wrong argument count for function " + getName(), ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH};

            range_col = arguments[current_arguments_index].column;
            range_col_type = arguments[current_arguments_index].type;

            if (!(range_col_type->isValueRepresentedByInteger() && range_col_type->getSizeOfValueInMemory() <= sizeof(Int64)))
                throw Exception{"Illegal type " + range_col_type->getName() + " of fourth argument of function "
                        + getName() + " must be convertible to Int64.",
                    ErrorCodes::ILLEGAL_COLUMN};

            ++current_arguments_index;
        }

        Columns default_cols;

        if (dictionary_get_function_type == DictionaryGetFunctionType::getOrDefault)
        {
            if (current_arguments_index >= arguments.size())
                throw Exception{"Wrong argument count for function " + getName(), ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH};

            const auto & column_before_cast = arguments[current_arguments_index];

            if (const DataTypeTuple * type_tuple = typeid_cast<const DataTypeTuple *>(column_before_cast.type.get()))
            {
                const DataTypes & nested_types = type_tuple->getElements();

                for (const auto & nested_type : nested_types)
                    if (nested_type->isNullable())
                        throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT, "Wrong argument for function ({}) default values column nullable is not supported", getName());
            }
            else if (column_before_cast.type->isNullable())
                throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT, "Wrong argument for function ({}) default values column nullable is not supported", getName());

            auto result_type_no_nullable = removeNullable(result_type);

            ColumnWithTypeAndName column_to_cast = {column_before_cast.column->convertToFullColumnIfConst(), column_before_cast.type, column_before_cast.name};

            auto result = castColumnAccurate(column_to_cast, result_type_no_nullable);

            if (attribute_names.size() > 1)
            {
                const auto * tuple_column = checkAndGetColumn<ColumnTuple>(result.get());

                if (!tuple_column)
                    throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
                        "Wrong argument for function ({}) default values column must be tuple", getName());

                if (tuple_column->tupleSize() != attribute_names.size())
                    throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
                        "Wrong argument for function ({}) default values tuple column must contain same column size as requested attributes",
                        getName());

                default_cols = tuple_column->getColumnsCopy();
            }
            else
                default_cols.emplace_back(result);
        }
        else
        {
            for (size_t i = 0; i < attribute_names.size(); ++i)
                default_cols.emplace_back(nullptr);
        }

        ColumnPtr result;

        const ColumnWithTypeAndName & key_col_with_type = arguments[2];
        const auto key_column = key_col_with_type.column;

        if (dictionary_key_type == DictionaryKeyType::simple)
        {
            if (!WhichDataType(key_col_with_type.type).isUInt64())
                 throw Exception(
                     ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
                     "Third argument of function ({}) must be uint64 when dictionary is simple. Actual type ({}).",
                     getName(),
                     key_col_with_type.type->getName());

            if (attribute_names.size() > 1)
            {
                const auto & result_tuple_type = assert_cast<const DataTypeTuple &>(*result_type);

                Columns result_columns = dictionary->getColumns(
                    attribute_names,
                    result_tuple_type.getElements(),
                    {key_column},
                    {std::make_shared<DataTypeUInt64>()},
                    default_cols);

                result = ColumnTuple::create(std::move(result_columns));
            }
            else
                result = dictionary->getColumn(
                    attribute_names[0],
                    result_type,
                    {key_column},
                    {std::make_shared<DataTypeUInt64>()},
                    default_cols.front());
        }
        else if (dictionary_key_type == DictionaryKeyType::complex)
        {
            if (!isTuple(key_col_with_type.type))
                 throw Exception(
                     ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
                     "Third argument of function ({}) must be tuple when dictionary is complex. Actual type ({}).",
                     getName(),
                     key_col_with_type.type->getName());

            /// Functions in external dictionaries_loader only support full-value (not constant) columns with keys.
            ColumnPtr key_column_full = key_col_with_type.column->convertToFullColumnIfConst();

            if (!isTuple(key_col_with_type.type))
                throw Exception(
                    ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
                    "Third argument of function ({}) must be tuple when dictionary is complex. Actual type ({}).",
                    getName(),
                    key_col_with_type.type->getName());

            const auto & key_columns = typeid_cast<const ColumnTuple &>(*key_column_full).getColumnsCopy();
            const auto & key_types = static_cast<const DataTypeTuple &>(*key_col_with_type.type).getElements();

            if (attribute_names.size() > 1)
            {
                const auto & result_tuple_type = assert_cast<const DataTypeTuple &>(*result_type);

                Columns result_columns = dictionary->getColumns(
                    attribute_names,
                    result_tuple_type.getElements(),
                    key_columns,
                    key_types,
                    default_cols);

                result = ColumnTuple::create(std::move(result_columns));
            }
            else
                result = dictionary->getColumn(
                    attribute_names[0],
                    result_type,
                    key_columns,
                    key_types,
                    default_cols.front());
        }
        else if (dictionary_key_type == DictionaryKeyType::range)
        {
            if (!WhichDataType(key_col_with_type.type).isUInt64())
                 throw Exception(
                     ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
                     "Third argument of function ({}) must be uint64 when dictionary is range. Actual type ({}).",
                     getName(),
                     key_col_with_type.type->getName());

            if (attribute_names.size() > 1)
            {
                const auto & result_tuple_type = assert_cast<const DataTypeTuple &>(*result_type);

                Columns result_columns = dictionary->getColumns(
                    attribute_names,
                    result_tuple_type.getElements(),
                    {key_column, range_col},
                    {std::make_shared<DataTypeUInt64>(), range_col_type},
                    default_cols);

                result = ColumnTuple::create(std::move(result_columns));
            }
            else
                result = dictionary->getColumn(
                    attribute_names[0],
                    result_type,
                    {key_column, range_col},
                    {std::make_shared<DataTypeUInt64>(), range_col_type},
                    default_cols.front());
        }
        else
            throw Exception{"Unknown dictionary identifier type", ErrorCodes::BAD_ARGUMENTS};

        return result;
    }

private:

    Strings getAttributeNamesFromColumn(const ColumnPtr & column, const DataTypePtr & type) const
    {
        Strings attribute_names;

        if (const auto * name_col = checkAndGetColumnConst<ColumnString>(column.get()))
            attribute_names.emplace_back(name_col->getValue<String>());
        else if (const auto * tuple_col_const = checkAndGetColumnConst<ColumnTuple>(column.get()))
        {
            const ColumnTuple & tuple_col = assert_cast<const ColumnTuple &>(tuple_col_const->getDataColumn());
            size_t tuple_size = tuple_col.tupleSize();

            if (tuple_size < 1)
                throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
                    "Tuple second argument of function ({}) must contain multiple constant string columns");

            for (size_t i = 0; i < tuple_col.tupleSize(); ++i)
            {
                const auto * tuple_column = tuple_col.getColumnPtr(i).get();

                const auto * attribute_name_column = checkAndGetColumn<ColumnString>(tuple_column);

                if (!attribute_name_column)
                    throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
                        "Tuple second argument of function ({}) must contain multiple constant string columns",
                        getName());

                attribute_names.emplace_back(attribute_name_column->getDataAt(0));
            }
        }
        else
            throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
                "Illegal type ({}) of second argument of function ({}), expected a const string or const tuple of const strings.",
                type->getName(),
                getName());

        return attribute_names;
    }

    mutable FunctionDictHelper helper;
};

template <typename DataType, typename Name, DictionaryGetFunctionType dictionary_get_function_type>
class FunctionDictGetImpl final : public IFunction
{
    using Type = typename DataType::FieldType;

public:
    static constexpr auto name = Name::name;

    static FunctionPtr create(const Context &context)
    {
        return std::make_shared<FunctionDictGetImpl>(context);
    }

    explicit FunctionDictGetImpl(const Context & context_) : impl(context_) {}

    String getName() const override { return name; }

private:
    size_t getNumberOfArguments() const override { return 0; }

    bool isVariadic() const override { return true; }

    bool useDefaultImplementationForConstants() const final { return true; }

    bool isDeterministic() const override { return false; }

    ColumnNumbers getArgumentsThatAreAlwaysConstant() const final { return {0, 1}; }

    bool isInjective(const ColumnsWithTypeAndName & sample_columns) const override
    {
        return impl.isInjective(sample_columns);
    }

    DataTypePtr getReturnTypeImpl(const DataTypes &) const override
    {
        DataTypePtr result;

        if constexpr (IsDataTypeDecimal<DataType>)
            result = std::make_shared<DataType>(DataType::maxPrecision(), 0);
        else
            result = std::make_shared<DataType>();

        return result;
    }

    ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const override
    {
        auto return_type = impl.getReturnTypeImpl(arguments);

        if (!areTypesEqual(return_type, result_type))
            throw Exception{"Dictionary attribute has different type " + return_type->getName() + " expected " + result_type->getName(),
                    ErrorCodes::TYPE_MISMATCH};

        return impl.executeImpl(arguments, return_type, input_rows_count);
    }

    static bool areTypesEqual(const DataTypePtr & lhs, const DataTypePtr & rhs)
    {
        return removeNullable(recursiveRemoveLowCardinality(lhs))->equals(*removeNullable(recursiveRemoveLowCardinality(rhs)));
    }

    const FunctionDictGetNoType<dictionary_get_function_type> impl;
};

template<typename DataType, typename Name>
using FunctionDictGet = FunctionDictGetImpl<DataType, Name, DictionaryGetFunctionType::get>;

struct NameDictGetUInt8 { static constexpr auto name = "dictGetUInt8"; };
struct NameDictGetUInt16 { static constexpr auto name = "dictGetUInt16"; };
struct NameDictGetUInt32 { static constexpr auto name = "dictGetUInt32"; };
struct NameDictGetUInt64 { static constexpr auto name = "dictGetUInt64"; };
struct NameDictGetInt8 { static constexpr auto name = "dictGetInt8"; };
struct NameDictGetInt16 { static constexpr auto name = "dictGetInt16"; };
struct NameDictGetInt32 { static constexpr auto name = "dictGetInt32"; };
struct NameDictGetInt64 { static constexpr auto name = "dictGetInt64"; };
struct NameDictGetFloat32 { static constexpr auto name = "dictGetFloat32"; };
struct NameDictGetFloat64 { static constexpr auto name = "dictGetFloat64"; };
struct NameDictGetDate { static constexpr auto name = "dictGetDate"; };
struct NameDictGetDateTime { static constexpr auto name = "dictGetDateTime"; };
struct NameDictGetUUID { static constexpr auto name = "dictGetUUID"; };
struct NameDictGetDecimal32 { static constexpr auto name = "dictGetDecimal32"; };
struct NameDictGetDecimal64 { static constexpr auto name = "dictGetDecimal64"; };
struct NameDictGetDecimal128 { static constexpr auto name = "dictGetDecimal128"; };
struct NameDictGetString { static constexpr auto name = "dictGetString"; };

using FunctionDictGetUInt8 = FunctionDictGet<DataTypeUInt8, NameDictGetUInt8>;
using FunctionDictGetUInt16 = FunctionDictGet<DataTypeUInt16, NameDictGetUInt16>;
using FunctionDictGetUInt32 = FunctionDictGet<DataTypeUInt32, NameDictGetUInt32>;
using FunctionDictGetUInt64 = FunctionDictGet<DataTypeUInt64, NameDictGetUInt64>;
using FunctionDictGetInt8 = FunctionDictGet<DataTypeInt8, NameDictGetInt8>;
using FunctionDictGetInt16 = FunctionDictGet<DataTypeInt16, NameDictGetInt16>;
using FunctionDictGetInt32 = FunctionDictGet<DataTypeInt32, NameDictGetInt32>;
using FunctionDictGetInt64 = FunctionDictGet<DataTypeInt64, NameDictGetInt64>;
using FunctionDictGetFloat32 = FunctionDictGet<DataTypeFloat32, NameDictGetFloat32>;
using FunctionDictGetFloat64 = FunctionDictGet<DataTypeFloat64, NameDictGetFloat64>;
using FunctionDictGetDate = FunctionDictGet<DataTypeDate, NameDictGetDate>;
using FunctionDictGetDateTime = FunctionDictGet<DataTypeDateTime, NameDictGetDateTime>;
using FunctionDictGetUUID = FunctionDictGet<DataTypeUUID, NameDictGetUUID>;
using FunctionDictGetDecimal32 = FunctionDictGet<DataTypeDecimal<Decimal32>, NameDictGetDecimal32>;
using FunctionDictGetDecimal64 = FunctionDictGet<DataTypeDecimal<Decimal64>, NameDictGetDecimal64>;
using FunctionDictGetDecimal128 = FunctionDictGet<DataTypeDecimal<Decimal128>, NameDictGetDecimal128>;
using FunctionDictGetString = FunctionDictGet<DataTypeString, NameDictGetString>;

template<typename DataType, typename Name>
using FunctionDictGetOrDefault = FunctionDictGetImpl<DataType, Name, DictionaryGetFunctionType::getOrDefault>;

struct NameDictGetUInt8OrDefault { static constexpr auto name = "dictGetUInt8OrDefault"; };
struct NameDictGetUInt16OrDefault { static constexpr auto name = "dictGetUInt16OrDefault"; };
struct NameDictGetUInt32OrDefault { static constexpr auto name = "dictGetUInt32OrDefault"; };
struct NameDictGetUInt64OrDefault { static constexpr auto name = "dictGetUInt64OrDefault"; };
struct NameDictGetInt8OrDefault { static constexpr auto name = "dictGetInt8OrDefault"; };
struct NameDictGetInt16OrDefault { static constexpr auto name = "dictGetInt16OrDefault"; };
struct NameDictGetInt32OrDefault { static constexpr auto name = "dictGetInt32OrDefault"; };
struct NameDictGetInt64OrDefault { static constexpr auto name = "dictGetInt64OrDefault"; };
struct NameDictGetFloat32OrDefault { static constexpr auto name = "dictGetFloat32OrDefault"; };
struct NameDictGetFloat64OrDefault { static constexpr auto name = "dictGetFloat64OrDefault"; };
struct NameDictGetDateOrDefault { static constexpr auto name = "dictGetDateOrDefault"; };
struct NameDictGetDateTimeOrDefault { static constexpr auto name = "dictGetDateTimeOrDefault"; };
struct NameDictGetUUIDOrDefault { static constexpr auto name = "dictGetUUIDOrDefault"; };
struct NameDictGetDecimal32OrDefault { static constexpr auto name = "dictGetDecimal32OrDefault"; };
struct NameDictGetDecimal64OrDefault { static constexpr auto name = "dictGetDecimal64OrDefault"; };
struct NameDictGetDecimal128OrDefault { static constexpr auto name = "dictGetDecimal128OrDefault"; };
struct NameDictGetStringOrDefault { static constexpr auto name = "dictGetStringOrDefault"; };

using FunctionDictGetUInt8OrDefault = FunctionDictGetOrDefault<DataTypeUInt8, NameDictGetUInt8OrDefault>;
using FunctionDictGetUInt16OrDefault = FunctionDictGetOrDefault<DataTypeUInt16, NameDictGetUInt16OrDefault>;
using FunctionDictGetUInt32OrDefault = FunctionDictGetOrDefault<DataTypeUInt32, NameDictGetUInt32OrDefault>;
using FunctionDictGetUInt64OrDefault = FunctionDictGetOrDefault<DataTypeUInt64, NameDictGetUInt64OrDefault>;
using FunctionDictGetInt8OrDefault = FunctionDictGetOrDefault<DataTypeInt8, NameDictGetInt8OrDefault>;
using FunctionDictGetInt16OrDefault = FunctionDictGetOrDefault<DataTypeInt16, NameDictGetInt16OrDefault>;
using FunctionDictGetInt32OrDefault = FunctionDictGetOrDefault<DataTypeInt32, NameDictGetInt32OrDefault>;
using FunctionDictGetInt64OrDefault = FunctionDictGetOrDefault<DataTypeInt64, NameDictGetInt64OrDefault>;
using FunctionDictGetFloat32OrDefault = FunctionDictGetOrDefault<DataTypeFloat32, NameDictGetFloat32OrDefault>;
using FunctionDictGetFloat64OrDefault = FunctionDictGetOrDefault<DataTypeFloat64, NameDictGetFloat64OrDefault>;
using FunctionDictGetDateOrDefault = FunctionDictGetOrDefault<DataTypeDate, NameDictGetDateOrDefault>;
using FunctionDictGetDateTimeOrDefault = FunctionDictGetOrDefault<DataTypeDateTime, NameDictGetDateTimeOrDefault>;
using FunctionDictGetUUIDOrDefault = FunctionDictGetOrDefault<DataTypeUUID, NameDictGetUUIDOrDefault>;
using FunctionDictGetDecimal32OrDefault = FunctionDictGetOrDefault<DataTypeDecimal<Decimal32>, NameDictGetDecimal32OrDefault>;
using FunctionDictGetDecimal64OrDefault = FunctionDictGetOrDefault<DataTypeDecimal<Decimal64>, NameDictGetDecimal64OrDefault>;
using FunctionDictGetDecimal128OrDefault = FunctionDictGetOrDefault<DataTypeDecimal<Decimal128>, NameDictGetDecimal128OrDefault>;
using FunctionDictGetStringOrDefault = FunctionDictGetOrDefault<DataTypeString, NameDictGetStringOrDefault>;

/// Functions to work with hierarchies.

class FunctionDictGetHierarchy final : public IFunction
{
public:
    static constexpr auto name = "dictGetHierarchy";

    static FunctionPtr create(const Context & context)
    {
        return std::make_shared<FunctionDictGetHierarchy>(context);
    }

    explicit FunctionDictGetHierarchy(const Context & context_) : helper(context_) {}

    String getName() const override { return name; }

private:
    size_t getNumberOfArguments() const override { return 2; }
    bool isInjective(const ColumnsWithTypeAndName & /*sample_columns*/) const override { return true; }

    bool useDefaultImplementationForConstants() const final { return true; }
    ColumnNumbers getArgumentsThatAreAlwaysConstant() const final { return {0}; }

    DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
    {
        if (!isString(arguments[0]))
            throw Exception{"Illegal type " + arguments[0]->getName() + " of first argument of function " + getName()
                + ", expected a string.", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};

        if (!WhichDataType(arguments[1]).isUInt64())
            throw Exception{"Illegal type " + arguments[1]->getName() + " of second argument of function " + getName()
                + ", must be UInt64.", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};

        return std::make_shared<DataTypeArray>(std::make_shared<DataTypeUInt64>());
    }

    bool isDeterministic() const override { return false; }

    ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const override
    {
        if (input_rows_count == 0)
            return result_type->createColumn();

        auto dict = helper.getDictionary(arguments[0]);
        ColumnPtr res;

        /// TODO: Rewrite this
        if (!((res = executeDispatch<FlatDictionary>(arguments, result_type, dict))
            || (res = executeDispatch<DirectDictionary<DictionaryKeyType::simple>>(arguments, result_type, dict))
            || (res = executeDispatch<HashedDictionary>(arguments, result_type, dict))
            || (res = executeDispatch<CacheDictionary<DictionaryKeyType::simple>>(arguments, result_type, dict))))
            throw Exception{"Unsupported dictionary type " + dict->getTypeName(), ErrorCodes::UNKNOWN_TYPE};

        return res;
    }

    template <typename DictionaryType>
    ColumnPtr executeDispatch(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, const std::shared_ptr<const IDictionaryBase> & dict_ptr) const
    {
        const auto * dict = typeid_cast<const DictionaryType *>(dict_ptr.get());
        if (!dict)
            return nullptr;

        if (!dict->hasHierarchy())
            throw Exception{"Dictionary does not have a hierarchy", ErrorCodes::UNSUPPORTED_METHOD};

        const auto get_hierarchies = [&] (const PaddedPODArray<UInt64> & in, PaddedPODArray<UInt64> & out, PaddedPODArray<UInt64> & offsets)
        {
            const auto size = in.size();

            /// copy of `in` array
            auto in_array = std::make_unique<PaddedPODArray<UInt64>>(std::begin(in), std::end(in));
            /// used for storing and handling result of ::toParent call
            auto out_array = std::make_unique<PaddedPODArray<UInt64>>(size);
            /// resulting hierarchies
            std::vector<std::vector<IDictionary::Key>> hierarchies(size);    /// TODO Bad code, poor performance.

            /// total number of non-zero elements, used for allocating all the required memory upfront
            size_t total_count = 0;

            while (true)
            {
                auto all_zeroes = true;

                /// erase zeroed identifiers, store non-zeroed ones
                for (const auto i : ext::range(0, size))
                {
                    const auto id = (*in_array)[i];
                    if (0 == id)
                        continue;


                    auto & hierarchy = hierarchies[i];

                    /// Checking for loop
                    if (std::find(std::begin(hierarchy), std::end(hierarchy), id) != std::end(hierarchy))
                        continue;

                    all_zeroes = false;
                    /// place id at it's corresponding place
                    hierarchy.push_back(id);

                    ++total_count;
                }

                if (all_zeroes)
                    break;

                /// translate all non-zero identifiers at once
                dict->toParent(*in_array, *out_array);

                /// we're going to use the `in_array` from this iteration as `out_array` on the next one
                std::swap(in_array, out_array);
            }

            out.reserve(total_count);
            offsets.resize(size);

            for (const auto i : ext::range(0, size))
            {
                const auto & ids = hierarchies[i];
                out.insert_assume_reserved(std::begin(ids), std::end(ids));
                offsets[i] = out.size();
            }
        };

        const auto * id_col_untyped = arguments[1].column.get();
        if (const auto * id_col = checkAndGetColumn<ColumnUInt64>(id_col_untyped))
        {
            const auto & in = id_col->getData();
            auto backend = ColumnUInt64::create();
            auto offsets = ColumnArray::ColumnOffsets::create();
            get_hierarchies(in, backend->getData(), offsets->getData());
            return ColumnArray::create(std::move(backend), std::move(offsets));
        }
        else if (const auto * id_col_const = checkAndGetColumnConst<ColumnVector<UInt64>>(id_col_untyped))
        {
            const PaddedPODArray<UInt64> in(1, id_col_const->getValue<UInt64>());
            auto backend = ColumnUInt64::create();
            auto offsets = ColumnArray::ColumnOffsets::create();
            get_hierarchies(in, backend->getData(), offsets->getData());
            auto array = ColumnArray::create(std::move(backend), std::move(offsets));
            return result_type->createColumnConst(id_col_const->size(), (*array)[0].get<Array>());
        }
        else
            throw Exception{"Second argument of function " + getName() + " must be UInt64", ErrorCodes::ILLEGAL_COLUMN};
    }

    mutable FunctionDictHelper helper;
};


class FunctionDictIsIn final : public IFunction
{
public:
    static constexpr auto name = "dictIsIn";

    static FunctionPtr create(const Context & context)
    {
        return std::make_shared<FunctionDictIsIn>(context);
    }

    explicit FunctionDictIsIn(const Context & context_)
        : helper(context_) {}

    String getName() const override { return name; }

private:
    size_t getNumberOfArguments() const override { return 3; }

    bool useDefaultImplementationForConstants() const final { return true; }
    ColumnNumbers getArgumentsThatAreAlwaysConstant() const final { return {0}; }

    DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
    {
        if (!isString(arguments[0]))
            throw Exception{"Illegal type " + arguments[0]->getName() + " of first argument of function " + getName()
                + ", expected a string.", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};

        if (!WhichDataType(arguments[1]).isUInt64())
            throw Exception{"Illegal type " + arguments[1]->getName() + " of second argument of function " + getName()
                + ", must be UInt64.", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};

        if (!WhichDataType(arguments[2]).isUInt64())
            throw Exception{"Illegal type " + arguments[2]->getName() + " of third argument of function " + getName()
                + ", must be UInt64.", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};

        return std::make_shared<DataTypeUInt8>();
    }

    bool isDeterministic() const override { return false; }

    ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const override
    {
        if (input_rows_count == 0)
            return result_type->createColumn();

        auto dict = helper.getDictionary(arguments[0]);

        ColumnPtr res;
        if (!((res = executeDispatch<FlatDictionary>(arguments, dict))
            || (res = executeDispatch<DirectDictionary<DictionaryKeyType::simple>>(arguments, dict))
            || (res = executeDispatch<HashedDictionary>(arguments, dict))
            || (res = executeDispatch<CacheDictionary<DictionaryKeyType::simple>>(arguments, dict))))
            throw Exception{"Unsupported dictionary type " + dict->getTypeName(), ErrorCodes::UNKNOWN_TYPE};

        return res;
    }

    template <typename DictionaryType>
    ColumnPtr executeDispatch(const ColumnsWithTypeAndName & arguments, const std::shared_ptr<const IDictionaryBase> & dict_ptr) const
    {
        const auto * dict = typeid_cast<const DictionaryType *>(dict_ptr.get());
        if (!dict)
            return nullptr;

        if (!dict->hasHierarchy())
            throw Exception{"Dictionary does not have a hierarchy", ErrorCodes::UNSUPPORTED_METHOD};

        const auto * child_id_col_untyped = arguments[1].column.get();
        const auto * ancestor_id_col_untyped = arguments[2].column.get();

        if (const auto * child_id_col = checkAndGetColumn<ColumnUInt64>(child_id_col_untyped))
            return execute(dict, child_id_col, ancestor_id_col_untyped);
        else if (const auto * child_id_col_const = checkAndGetColumnConst<ColumnVector<UInt64>>(child_id_col_untyped))
            return execute(dict, child_id_col_const, ancestor_id_col_untyped);
        else
            throw Exception{"Illegal column " + child_id_col_untyped->getName()
                + " of second argument of function " + getName(), ErrorCodes::ILLEGAL_COLUMN};
    }

    template <typename DictionaryType>
    ColumnPtr execute(const DictionaryType * dict,
                 const ColumnUInt64 * child_id_col, const IColumn * ancestor_id_col_untyped) const
    {
        if (const auto * ancestor_id_col = checkAndGetColumn<ColumnUInt64>(ancestor_id_col_untyped))
        {
            auto out = ColumnUInt8::create();

            const auto & child_ids = child_id_col->getData();
            const auto & ancestor_ids = ancestor_id_col->getData();
            auto & data = out->getData();
            const auto size = child_id_col->size();
            data.resize(size);

            dict->isInVectorVector(child_ids, ancestor_ids, data);
            return out;
        }
        else if (const auto * ancestor_id_col_const = checkAndGetColumnConst<ColumnVector<UInt64>>(ancestor_id_col_untyped))
        {
            auto out = ColumnUInt8::create();

            const auto & child_ids = child_id_col->getData();
            const auto ancestor_id = ancestor_id_col_const->getValue<UInt64>();
            auto & data = out->getData();
            const auto size = child_id_col->size();
            data.resize(size);

            dict->isInVectorConstant(child_ids, ancestor_id, data);
            return out;
        }
        else
        {
            throw Exception{"Illegal column " + ancestor_id_col_untyped->getName()
                + " of third argument of function " + getName(), ErrorCodes::ILLEGAL_COLUMN};
        }
    }

    template <typename DictionaryType>
    ColumnPtr execute(const DictionaryType * dict, const ColumnConst * child_id_col, const IColumn * ancestor_id_col_untyped) const
    {
        if (const auto * ancestor_id_col = checkAndGetColumn<ColumnUInt64>(ancestor_id_col_untyped))
        {
            auto out = ColumnUInt8::create();

            const auto child_id = child_id_col->getValue<UInt64>();
            const auto & ancestor_ids = ancestor_id_col->getData();
            auto & data = out->getData();
            const auto size = child_id_col->size();
            data.resize(size);

            dict->isInConstantVector(child_id, ancestor_ids, data);
            return out;
        }
        else if (const auto * ancestor_id_col_const = checkAndGetColumnConst<ColumnVector<UInt64>>(ancestor_id_col_untyped))
        {
            const auto child_id = child_id_col->getValue<UInt64>();
            const auto ancestor_id = ancestor_id_col_const->getValue<UInt64>();
            UInt8 res = 0;

            dict->isInConstantConstant(child_id, ancestor_id, res);
            return DataTypeUInt8().createColumnConst(child_id_col->size(), res);
        }
        else
            throw Exception{"Illegal column " + ancestor_id_col_untyped->getName()
                + " of third argument of function " + getName(), ErrorCodes::ILLEGAL_COLUMN};
    }

    mutable FunctionDictHelper helper;
};

}