示例#1
0
void DatabaseOrdinary::renameTable(
	const Context & context, const String & table_name, IDatabase & to_database, const String & to_table_name)
{
	DatabaseOrdinary * to_database_concrete = typeid_cast<DatabaseOrdinary *>(&to_database);

	if (!to_database_concrete)
		throw Exception("Moving tables between databases of different engines is not supported", ErrorCodes::NOT_IMPLEMENTED);

	StoragePtr table = tryGetTable(table_name);

	if (!table)
		throw Exception("Table " + name + "." + table_name + " doesn't exist.", ErrorCodes::TABLE_ALREADY_EXISTS);

	/// Уведомляем таблицу о том, что она переименовывается. Если таблица не поддерживает переименование - кинется исключение.
	try
	{
		table->rename(context.getPath() + "/data/" + escapeForFileName(to_database_concrete->name) + "/",
			to_database_concrete->name,
			to_table_name);
	}
	catch (const Poco::Exception & e)
	{
		/// Более хорошая диагностика.
		throw Exception{e};
	}

	ASTPtr ast = getCreateQueryImpl(path, table_name);
	ASTCreateQuery & ast_create_query = typeid_cast<ASTCreateQuery &>(*ast);
	ast_create_query.table = to_table_name;

	/// NOTE Неатомарно.
	to_database_concrete->createTable(to_table_name, table, ast, table->getName());
	removeTable(table_name);
}
示例#2
0
StorageMerge::StorageListWithLocks StorageMerge::getSelectedTables(const ASTPtr & query, bool has_virtual_column, bool get_lock) const
{
    StorageListWithLocks selected_tables;
    DatabasePtr database = global_context.getDatabase(source_database);
    DatabaseIteratorPtr iterator = database->getIterator(global_context);

    auto virtual_column = ColumnString::create();

    while (iterator->isValid())
    {
        if (table_name_regexp.match(iterator->name()))
        {
            StoragePtr storage = iterator->table();

            if (query && typeid_cast<ASTSelectQuery *>(query.get())->prewhere_expression && !storage->supportsPrewhere())
                throw Exception("Storage " + storage->getName() + " doesn't support PREWHERE.", ErrorCodes::ILLEGAL_PREWHERE);

            if (storage.get() != this)
            {
                virtual_column->insert(storage->getTableName());
                selected_tables.emplace_back(storage, get_lock ? storage->lockStructure(false) : TableStructureReadLockPtr{});
            }
        }

        iterator->next();
    }

    if (has_virtual_column)
    {
        Block virtual_columns_block = Block{ColumnWithTypeAndName(std::move(virtual_column), std::make_shared<DataTypeString>(), "_table")};
        VirtualColumnUtils::filterBlockWithQuery(query, virtual_columns_block, global_context);
        auto values = VirtualColumnUtils::extractSingleValueFromBlock<String>(virtual_columns_block, "_table");

        /// Remove unused tables from the list
        selected_tables.remove_if([&] (const auto & elem) { return values.find(elem.first->getTableName()) == values.end(); });
    }

    return selected_tables;
}
String InterpreterCreateQuery::setEngine(
    ASTCreateQuery & create, const StoragePtr & as_storage) const
{
    String storage_name;

    auto set_engine = [&](const char * engine)
    {
        storage_name = engine;
        auto func = std::make_shared<ASTFunction>();
        func->name = engine;
        create.storage = func;
    };

    if (create.storage)
    {
        storage_name = typeid_cast<ASTFunction &>(*create.storage).name;
    }
    else if (!create.as_table.empty())
    {
        /// NOTE Получение структуры у таблицы, указанной в AS делается не атомарно с созданием таблицы.

        String as_database_name = create.as_database.empty() ? context.getCurrentDatabase() : create.as_database;
        String as_table_name = create.as_table;

        storage_name = as_storage->getName();
        create.storage = typeid_cast<const ASTCreateQuery &>(*context.getCreateQuery(as_database_name, as_table_name)).storage;
    }
    else if (create.is_temporary)
        set_engine("Memory");
    else if (create.is_view)
        set_engine("View");
    else if (create.is_materialized_view)
        set_engine("MaterializedView");
    else
        throw Exception("Incorrect CREATE query: required ENGINE.", ErrorCodes::ENGINE_REQUIRED);

    return storage_name;
}