🔥 The DB Grill 🔥

Ah, yes. Another masterpiece. It's always so refreshing to read a thoughtful piece that begins with the classic "two hard problems" joke. It lets me know we're in the hands of a true practitioner, someone who has clearly never had to deal with the actual three hard problems of production systems: DNS propagation, expired TLS certificates, and a junior engineer being given root access on a Friday afternoon.

I'm particularly inspired by the breezy confidence with which "caching" is presented as a fundamental strategy. It's so elegant in theory. Just a simple key-value store that makes everything magically faster. It gives me the same warm, fuzzy feeling I get when a project manager shows me a flowchart where one of the boxes just says "AI/ML."

I can already see the change request now. It'll be a one-line ticket: "Implement new distributed caching layer for performance." And it will come with a whole host of beautiful promises.

My favorite, of course, will be the "zero-downtime" migration. It's my favorite phrase in the English language, a beautiful little lie we tell ourselves before the ritual sacrifice of a holiday weekend. I can already picture the game plan: a "simple" feature flag, a "painless" data backfill script, and a "seamless" cutover.

And I can also picture myself, at 3:15 AM on the Sunday of Memorial Day weekend, watching that "seamless" cutover trigger a thundering herd of cache misses that saturates every database connection and grinds the entire platform to a halt. The best part will be when we find out the new caching client has a subtle memory leak, but we won't know that for sure because the monitoring for it is still a story in the backlog, optimistically titled:

TODO: Add Prometheus exporters for NewShinyCacheThingy.

Oh, the monitoring! That’s the most forward-thinking part of these grand designs. The dashboards will be beautiful—full of green squares and vanity metrics like "Cache Hit Ratio," which will be a solid 99.8%. Of course, the 0.2% of misses will all be for the primary authentication service, but hey, that's a detail. The important thing is that the big number on the big screen looks good for the VPs. We'll get an alert when the system is well and truly dead, probably from a customer complaining on Twitter, which remains the most reliable end-to-end monitoring tool ever invented.

This whole proposal, with its clean lines and confident assertions, reminds me of my laptop lid. It’s a graveyard of vendor stickers from databases and platforms that were also going to solve one simple problem. There’s my shiny foil sticker for RethinkDB, right next to the holographic one from CoreOS, and let's not forget good old GobblinDB, which promised "petabyte-scale ingestion with ACID guarantees." They all looked fantastic in the blog posts, too.

So please, keep writing these. They're great. They give the developers a sense of purpose and the architects a new set of buzzwords for their slide decks.

You worry about cache invalidation. I'll be here, writing the post-mortem.