Brian LeBlanc-449582 (12/18/2008)
The premise of the question seemed to be “how to reduce the size of the snapshot?” and the answer is – Take another snapshot. I agree this is a crappy question…If a DBA came up to this scenario and was asked to reduce the size of the snapshop file by doing a backup and he replied “you can’t backup a Snapshot” and walked away, I would fire them. I would expect the DBA to say “I’ll take care of it” and do another snapshot to reduce the size.
I would expect the DBA to ask whether the snapshot was still required (because reports or other queries against the state of play as at that snapshot date were still needed) not to go off and replace the snapshot with a new one (and effectively make it impossible or at least very expensive to run those required queries and/or generate those required reports). I would also expect him to think I was an idiot for having raised the issue - if that snapshot was no longer required for report generation or ad hoc queries it should have been deleted already, so that its size would be irrelevant.
It's a good question not a crappy one, it rewuires you to think outside the narrow tecnhical box and consider real business needs.
Of course I intensely dislike the explanation, which doesn't attempt to explain why "take another snapshot" (as opposed to "delete the snapshot because it's obsolete") can never be the right answer (you might want to do that, but not because this one is too big, only because there is a frozen state you want to be able to run queries against and this snapshot doesn't represnt that state).