An SQL statement can be slow for a lot of reasons. Here, we will give a short list of these, with at least one way of recognizing each reason.
If the SQL statement is still running, look at Chapter 8, Monitoring and Diagnosis.
The core issues are likely to be one of these:
- You're asking it to do too much work
- Something is stopping it from doing the work
This might not sound that helpful at first, but it's good to know that there's nothing really magical going on that you can't understand...