yes. thats correct. and then run your content rebuilder afterwards.
Its advised that you should probably close your forums when making multiple wide-scale database changes such as these. the Content Rebuilder already closes your forum while its doing its work. In addition, if you are making changes that touch many of your largest tables at once, be sure to have a backup. A backup is something you hope you never need, but glad you have it if you ever do need it.
