> Instead, it's pointing out a risk that sometimes they are too good, leading to a system that can't function when the normal level of locality and memoization

> Instead, it's pointing out a risk that sometimes they are too good, leading to a system that can't function when the normal level of locality and memoization are not available. And at that point cache management starts to be a huge problem. Clearing caches becomes a death spiral because your system can't actually support your normal load. For example I worked with a large retailer, who had a giant monolithic enterprise Java ecommerce system. It was so slow that product detail pages took upwards of 30 seconds to render. There was a cache in front of that system (Ehcache), then a page-level cache (Varnish) in front of that, then finally Akamai took 98% of the load. Rollouts were terrifying, you cleared the cache and the site might come back up. Changing Akamai configuration was also similarly risky. It's critical that systems don't become cache dependent for load, they should be a performance boost, not a required component.