Have you ever heard the one about throwing hardware at a software problem? I have this nifty RAC system that supports some very public and very mission-critical apps, and one day (it was Sunday night) it starts choking. We’re getting enqueues. Slowly they start climbing. Ten nodes came to a crashing halt. I have now seen a ten-node RAC cluster come to crashing halt and completely lock up. Why, you ask? A simple SQL statement: DELETE FROM a WHERE b=c AND d=e;.