Method generate

src/Storages/StorageKeeperMap.cpp:322–350

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

    Chunk generate() override
    {
        auto component_guard = Coordination::setCurrentComponent("StorageKeeperMapSource::generate");
        if (it >= end)
        {
            it = {};
            return {};
        }

        using KeyType = typename KeyContainer::value_type;
        if constexpr (std::same_as<KeyType, Field>)
        {
            const auto & sample_block = getPort().getHeader();
            const auto & key_column_type = sample_block.getByName(storage.getPrimaryKey().at(0)).type;
            auto raw_keys = serializeKeysToRawString(it, end, key_column_type, max_block_size);

            for (auto & raw_key : raw_keys)
                raw_key = base64Encode(raw_key, /* url_encoding */ true);

            return storage.getBySerializedKeys(raw_keys, nullptr, with_version_column, getContext());
        }
        else
        {
            size_t elem_num = std::min(max_block_size, static_cast<size_t>(end - it));
            auto chunk = storage.getBySerializedKeys(std::span{it, it + elem_num}, nullptr, with_version_column, getContext());
            it += elem_num;
            return chunk;
        }
    }
};

StorageKeeperMap::StorageKeeperMap(