Function registerDatabaseMySQL

src/Databases/MySQL/DatabaseMySQL.cpp:595–840

void registerDatabaseMySQL(DatabaseFactory & factory);
void registerDatabaseMySQL(DatabaseFactory & factory)
{
    auto create_fn = [](const DatabaseFactory::Arguments & args)
    {
        auto * engine_define = args.create_query.storage;
        const ASTFunction * engine = engine_define->engine;
        const String & engine_name = engine_define->engine->name;
        if (!engine->arguments)
            throw Exception(ErrorCodes::BAD_ARGUMENTS, "Engine `{}` must have arguments", engine_name);

        StorageMySQL::Configuration configuration;
        ASTs & arguments = engine->arguments->children;
        auto mysql_settings = std::make_unique<MySQLSettings>();

        if (auto named_collection = tryGetNamedCollectionWithOverrides(arguments, args.context))
        {
            configuration = StorageMySQL::processNamedCollectionResult(*named_collection, *mysql_settings, args.context, false);
        }
        else
        {
            if (arguments.size() != 4)
                throw Exception(
                    ErrorCodes::BAD_ARGUMENTS,
                    "MySQL database require mysql_hostname, mysql_database_name, mysql_username, mysql_password arguments.");


            arguments[1] = evaluateConstantExpressionOrIdentifierAsLiteral(arguments[1], args.context);
            const auto & host_port = safeGetLiteralValue<String>(arguments[0], engine_name);

            if (engine_name == "MySQL")
            {
                size_t max_addresses = args.context->getSettingsRef()[Setting::glob_expansion_max_elements];
                configuration.addresses = parseRemoteDescriptionForExternalDatabase(host_port, max_addresses, 3306);
            }
            else
            {
                const auto & [remote_host, remote_port] = parseAddress(host_port, 3306);
                configuration.host = remote_host;
                configuration.port = remote_port;
            }

            configuration.database = safeGetLiteralValue<String>(arguments[1], engine_name);
            configuration.username = safeGetLiteralValue<String>(arguments[2], engine_name);
            configuration.password = safeGetLiteralValue<String>(arguments[3], engine_name);
        }
        mysql_settings->loadFromQueryContext(args.context, *engine_define);
        if (engine_define->settings)
            mysql_settings->loadFromQuery(*engine_define);

        auto mysql_pool = createMySQLPoolWithFailover(configuration, *mysql_settings);

        try
        {
            return make_shared<DatabaseMySQL>(
                args.context,
                args.database_name,
                args.metadata_path,
                engine_define,