I've confirmed that creating a new dialect as suggested in the description fixes failing tests listed in HHH-9444.

I suspect the following is also needed to support fractional seconds:

registerColumnType( Types.TIME, "time(6)" );

I'll add some tests using SimpleDateFormat.getTimeInstance( DateFormat.LONG ) to make sure fractional seconds are working properly.

I still have to look into whether Hibernate can support datetime and time, where n is the number of fractional digits precision (0 <= n <= 6).