Where database blog posts get flame-broiled to perfection
Ah, another dispatch from the front lines. It's always a pleasure to see Kyle's latest work. It’s like getting a beautifully rendered architectural blueprint of a train wreck in progress. A real artist.
He talks about getting an "intuitive feeling for what a system is doing." I remember that feeling. It was less intuition and more a cold, creeping dread that usually started around 3 AM the night before a big launch. You'd stare at the Grafana dashboards, which were all green of course, because the health checks only pinged /status and didn't, you know, actually check the data.
And this output, this is just a masterpiece of corporate doublespeak translated into code.
:lost-count 287249, :acknowledged-count 529369,
Oh, I remember these meetings. The project manager would stand up, point to the acknowledged-count and say, "Look at that throughput! We're knocking it out of the park!" while the one quiet engineer in the back who actually read the logs would just sink lower and lower in their chair. Half the data is gone, but the number of "acknowledgements" is high, so it's a success! We'll just call the lost data a "cache eviction event" in the press release. The three "recovered" writes are my favorite. They're not bugs, they're miracles. Spontaneous data resurrection. It's a feature we should have charged more for.
This new plot is just fantastic. A visual testament to the sheer, unadulterated chaos we called a "roadmap."
From this, we can see that data loss occurred in two large chunks, starting near a file-corruption operation at roughly 65 seconds and running until the end of the test.
I see it too. That first big chunk of red? That looks exactly like the time Dave from marketing tripped over the network cable to the primary, right after we'd pushed the "optimized" consensus protocol that skipped a few fsyncs to win a benchmark. The second chunk looks like the frantic scramble to "fix" it, which only corrupted the backups. It's not a diagnostic tool; it's a Rorschach test for engineering PTSD.
And the detail here is just exquisite.
He says, "this isn't a good plot yet," because he's "running out of colors." Of course you're running out of colors. There are only so many ways to paint a dumpster fire. We had more categories of failure than the marketing department had buzzwords. There was "data loss," "data corruption," "data that got stuck in the wrong data center and achieved sentience," and my personal favorite, "eventual consistency with the void."
He's calling them "op color plots" for now. How wonderfully sterile. At my old shop, we had a name for charts like this too. We called them "Performance Improvement Plan generators."
It’s a beautiful way to visualize a system lying to you at 6,800 records per second. Bravo.