Deadlock And Bad Users

How deadlock occurs

Imagine 100,000 transactions all trying to update the same row of the same table in the same database. Somebody is bound to get deadlocked. Once a single transaction with a lock on the user’s profile gets hung (because of the need for a connection from a different resource pool), all the other database transactions on that row get blocked. Pretty soon, every single request-handling thread gets used up with these bogus logins. As soon as that happens, the site is down.

So one group of bad users just blunder around leaving disaster in their wake. More crafty sorts, however, deliberately do abnormal things that just happen to have undesirable effects.

The first group isn’t deliberately malicious. They do damage inadvertently. This next group belongs in its own category, the parasitic industry.

Parasitic industry

An entire parasitic industry exists by consuming resources from other companies’ websites. Collectively known as competitive intelligence companies, these outfits leech data out of our system one web page at a time.

These companies will argue that their service is no different from a grocery store sending someone into a competing store with a ...