QMYSQL errors

Hallo

I got some failures with QMYSQL (QSQLITE will work)

My connection will be

Code:

if (dbType == "QSQLITE") {
        currentConnection = QSqlDatabase::addDatabase("QSQLITE", "CN");
        currentConnection.setDatabaseName(QString(dataDir + "/%1-%2.db").arg(date.year()).arg(basename));
    } else if (dbType == "QMYSQL") {
        QString userName = settings.value("DB_userName", "QRK").toString();
        QString password = settings.value("DB_password", "").toString();
        QString hostName = settings.value("DB_hostName", "localhost").toString();
 
        currentConnection = QSqlDatabase::addDatabase("QMYSQL", "CN");
        currentConnection.setHostName(hostName);
        currentConnection.setUserName(userName);
        currentConnection.setPassword(password);
        currentConnection.setConnectOptions("MYSQL_OPT_RECONNECT=1;MYSQL_OPT_CONNECT_TIMEOUT=86400;MYSQL_OPT_READ_TIMEOUT=60");
    }
 
    bool ok = currentConnection.open();

When i was connected i got, but not allways a SIGSEGV. When i remove the connection options i got "Lost connection to MySQL server during query"
no matter if MySQL Server is localhost or any Server on the Internet.

Yes, i search but found no solution. What can i do false?

OS: Linux Ubuntu (16.04 and 17.10) Server MariaDB from the Ubuntu Package

A Simply Query which returns one record and the Database holds max. 10 Entries.

Code:

QSqlDatabase dbc = QSqlDatabase::database("CN");
    QSqlQuery query(dbc);
 
    query.prepare("SELECT strValue FROM globals WHERE name='shopName'");
    query.exec();
    query.next();
 
    name = query.value(0).toString();

thx Chris