Caches, Modes, and Unstable Systems - Marc's Blog
Is your system having scaling trouble? A bit too slow? Sending too much traffic to the database? Add a caching layer! After all, caches are a best practice and a standard way to build systems. What trouble could following a best practice cause?
Hasnain says:
“Caches are based on assumptions. Fundamentally, a cache assumes that there's either some amount of temporal or spatial locality of access (i.e. if Alice is sending work now, she'll probably be sending more work soon, so it's efficient to keep Alice's stuff on deck), or there key distribution isn't uniform (i.e. Bob sends work every second, Alice sends work every day, so it's efficient to keep Bob's stuff on deck and fetch Alice's when we need it). These assumptions don't tend to be rigorous, or enforced in any way. They may change in ways that are invisible to most approaches to monitoring.”
Posted on 2021-08-28T00:21:38+0000