Thanks for letting me know. A nightly backup runs between 1 and 2 am, but ended at 1:37 this morning. So, I don't think that was it. Beyond that, I can't think of any other maintenance that runs at that time. So, I'd guess that we got hit by some sort of spider at that time. When automatic programs crawl the site, they often make unusual requests that drive the memory usage up. Once memory is exhausted, all kinds of weird things happen. I try to track down the problematic requests and either fix or block them. So, I'll see what I can find in the logs.