Yeah, I'm finding myself liking the idea of moving all of these things into vacuumingOptions so that we don't have to cart around so many bool arguments. Here's a new patch set that does it this way.
+1. Every time I modify a global variable, I hear my high school CS teacher scolding me.
The remaining question in my mind is where we should let the user know that we're in dry-run mode. The three options I see are 1) at the beginning of vacuumdb execution, 2) in the !quiet block for each database, and 3) in each command (via a comment). In v5, I've added a message to all three, but I'm eager to hear what folks think.
Looking at them, I think they're all good. I think #3 is a must-have in all circumstances. I wouldn't be mad if we removed #1 or #2, but I see the value in each of them.
