The question of how to identify indexes that could be dropped re-appeared (yet again) on the OTN database forum last week. It’s not really surprising that it recurs so regularly – the problem isn’t an easy one to solve but new (and even less new) users keep hoping that there’s a quick and easy solution.
There are, however, strategies and pointers that can help you to optimise the trade-off between effort, risk, and reward. Broadly the idea is to spend a small amount of effort finding a relatively small number of “expensive” indexes that might be safe to drop, so that when you do the detailed analysis you have a good chance that the time spent will be rewarded by a positive result.
Before we get to some results posted on OTN, it’s worth thinking about the global impact and what we’re trying to achieve, and the threats that go with our attempt to achieve it.