Where database blog posts get flame-broiled to perfection
Ah, another dispatch from the ivory tower, a beautiful theoretical landscape where data lives in abstract layers and performance scales infinitely with our cloud budget. "Disaggregation," they call it. I call it "multiplying the number of things that can fail by a factor of five." I've seen this movie before. The PowerPoint is always gorgeous. The production outage, less so.
Let's start with AlloyDB. A "layered design." Wonderful. What you call a "layered design," I call a "distributed monolith" with more network hops. So we have a primary node, read replicas, a shared storage engine, and log-processing servers. Fantastic. You're telling me I can scale my read pools "elastically with no data movement"? That sounds amazing, right up until the point that the "regional log storage" has a 30-second blip. Suddenly, those "log-processing servers" that continuously replay and materialize pages get stuck in a frantic catch-up loop, my read replicas are serving stale data, and the primary is thrashing because it can't get acknowledgements. But hey, at least we didn't have to move any data.
And this HTAP business, the "pluggable columnar engine" that automatically converts hot data. I can already see the JIRA ticket: "Critical dashboard is slow. Pls fix." I'll spend a week digging through logs only to find the "automatic" converter is in a deadlock with the garbage collector because a junior dev ran an analytics query that tried to join a billion-row transaction table against itself. But the marketing material said it was a unified, multi-format cache hierarchy!
Then we have Rockset, the "poster child for disaggregation." The AggregatorâLeafâTailer pattern. ALT. You know what ALT stands for in my world? Another Layer to Troubleshoot.
The key insight is that real-time analytics demands strict isolation between writes and reads.
That's a beautiful sentence. It deserves to be framed. In reality, that "strict isolation" lasts until a Tailer chokes on a slightly malformed Kafka message and stops ingesting data for an entire region. Now my "real-time" dashboards are 8 hours out of date, but my query latencies are fantastic because the Aggregators aren't getting any new data to work on! Mission accomplished? They brag that compaction can be handed off to stateless compute nodes. I've seen that trick. It's great, until one of those "stateless" jobs gets stuck, silently burning a hole in my cloud bill the size of a small nation's GDP while trying to merge two corrupted SST files from an S3 bucket with eventual consistency issues.
And the hits just keep on coming. Disaggregated Memory. My god. They claim today's datacenters "waste over half their DRAM." You know what I call that wasted DRAM? Headroom. I call it "the reason I can sleep through the night." Now you want me to use remote memory over a "coherent memory fabric"? I can't wait to debug an application that's crashing because of a memory corruption error happening in a server three racks away, triggered by a firmware bug on a CXL switch. The PagerDuty alert will just say SEGFAULT and my only clue will be a single dropped packet counter on a network port I don't even have access to.
Don't even get me started on the "open questions." These aren't research opportunities; they're the chapter titles of my post-mortem anthology.
The best part is the closing quote: "every database/systems assistant professor is going to get tenure figuring how to solve them." That's just perfect. They get tenure, and I get a 2 AM PagerDuty alert and another useless vendor sticker for my laptop lid. I've got a whole collection hereâghosts of databases past, each one promising a revolution. They promised zero-downtime, five-nines of availability, and effortless scale. In the end, all they delivered was a new and exciting way to ruin my weekend.
So yeah, disaggregation. It's a fantastic idea. Right up there with "move fast and break things." Except now, when we break things, they're in a dozen different pieces scattered across three availability zones. And I'm the one who has to find them all and glue them back together. Sigh. Pass the coffee. It's gonna be a long decade.