For anyone who might try compacting the database and wonder how long it’s going to take, it may take longer than you think, but don’t panic. As I invoked the command, the progress bar zoomed all the way across (as shown in the screenshot below), making me think it was finished in mere seconds, but then it sat there like that for a good 10 minutes, and I was worried that it had crashed. But as I started composing a query for this forum, I looked over and saw it had finished! And my 957.5-MB database is now a (relatively) trim 169.4 MB. Success!
This is because compacting the database is an atomic operation. That is, there’s no progress possible for it. It happens in one step. So you see what’s called the indeterminate progress indicator when it does that.