```
Caught exception while loading metadata: Code: 501, e.displayText() = DB::Exception: Cannot create MySQL database, because Code: 393, e.displayText() 
= DB::Exception: There is no query, Stack trace (when copying this message, always include the lines below):

0. /home/milovidov/ClickHouse/build_gcc9/../contrib/poco/Foundation/src/Exception.cpp:27: Poco::Exception::Exception(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, 
int) @ 0x1074687c in /usr/bin/clickhouse
1. /home/milovidov/ClickHouse/build_gcc9/../src/Common/Exception.cpp:37: DB::Exception::Exception(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, int) @ 0x7867c29 in
 /usr/bin/clickhouse
2. /home/milovidov/ClickHouse/build_gcc9/../contrib/libcxx/include/string:2134: DB::Context::getQueryContext() const (.cold) @ 0xd202416 in /usr/bin/clickhouse
3. /home/milovidov/ClickHouse/build_gcc9/../src/Interpreters/Context.h:457: DB::DatabaseConnectionMySQL::DatabaseConnectionMySQL(DB::Context const&, std::__1::basic_string<char, std::__1::char_traits<char>, std:
:__1::allocator<char> > const&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, DB::ASTStorage const*, std::__1::basic_string<char, std::__1::char_traits<char>, std:
:__1::allocator<char> > const&, mysqlxx::Pool&&) @ 0xd408d7c in /usr/bin/clickhouse
```

```
ATTACH DATABASE conv_main
ENGINE = MySQL('hostname:3306', 'db', 'metrika', 'password')
```
{
    std::vector<String> wait_update_tables_name;
    for (const auto & table_modification_time : tables_modification_time)
    {
        const auto & it = local_tables_cache.find(table_modification_time.first);
        
        if (it == local_tables_cache.end() || table_modification_time.second > it->second.first)
            wait_update_tables_name.emplace_back(table_modification_time.first);
    }
    std::map<String, NamesAndTypesList> tables_and_columns = fetchTablesColumnsList(wait_update_tables_name, context);
    for (const auto & table_and_columns : tables_and_columns)
    {
        const auto & table_name = table_and_columns.first;
        const auto & columns_name_and_type = table_and_columns.second;
        const auto & table_modification_time = tables_modification_time.at(table_name);
        const auto & iterator = local_tables_cache.find(table_name);
        if (iterator != local_tables_cache.end())
        {
            outdated_tables.emplace_back(iterator->second.second);
            local_tables_cache.erase(iterator);
        }
        local_tables_cache[table_name] = std::make_pair(table_modification_time, StorageMySQL::create(
            StorageID(database_name, table_name), std::move(mysql_pool), database_name_in_mysql, table_name,
            false, "", ColumnsDescription{columns_name_and_type}, ConstraintsDescription{}, global_context));
    }
}
std::map<String, UInt64> DatabaseConnectionMySQL::fetchTablesWithModificationTime() const