OpenKM has many interesting features, but requires some configuration process to show its full potential.
Forum rules: Please, before asking something see the documentation wiki or use the search feature of the forum. And remember we don't have a crystal ball or mental readers, so if you post about an issue tell us which OpenKM are you using and also the browser and operating system version. For more info read How to Report Bugs Effectively.
We suggest MySQL than HSQL. MySQL is more robust database and you can get more control than embeded database. About workflow there's no problem run on HSQL.