Avoiding Pitfalls of Common Caching Techniques
The practice of caching is about as effective at lowering latencies and load as it is at introducing nasty correctness problems. It is almost a law of nature that once you introduce a denormalization, it’s a matter of time before it diverges from the source of truth. The transient nature of caches makes problems very difficult to debug and clouds the matter in an extra layer of mystery. All this is to say that if you can live with the performance and load without caching, for the love of everything that’s good in the world, don’t add it. …
The data access layer of a million-dollar idea starts out as a single-server relational database. You’re hardly worried about scale issues – you have an application to write! However, if your million-dollar idea ends up being worth even $100K, you’ll likely find your database struggling to keep up with the scale. “No problem,” you say, “I’ll just add a bunch of read-only replicas. After all, my workload is read-heavy and distributing all of my reads between the replicas will significantly ease the load on my trusty old database.” …
About
