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);
}
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;
}