It really depends on how big the database is and what your computer is like, so it's impossible to give a generic "how long".
For future reference if you are importing a lot of hands you should use
Manual Import instead of
Auto Import as it is much faster - Auto Import is designed for importing as you play.
Your housekeeping may be taking longer than it should if you used "Update Cache" - currently for full updates "Rebuild Cache" is significantly faster - Update Cache should be used if you do a small manual import into an existing database or add any new statistics.
I expect that it will have finished by now - if not the best thing is to let it run, but you could terminate the process and run it again with Rebuild Cache instead if you prefer.