How Redis Actually Works — RAM, Single Thread, and the Expiry Behavior Nobody Explains

A RAM read takes about 100 nanoseconds. A disk read — even on a modern SSD — takes around 100,000 nanoseconds. That single gap explains most of Redis’s speed, before it does a single thing clever. Friend’s Link But RAM alone isn’t the full story. The other half is a design decision that looks like a limitation on paper — and turns out to be one of the smartest choices in the codebase. More on that in a moment. Here’s what’s actually happening inside Redis when your app talks to it. Why is Redis