Where database blog posts get flame-broiled to perfection
Alright, team, gather 'round. Another Tuesday, another deep-dive benchmark that looks great in a spreadsheet and will feel terrible in production. Iāve read the report, and I've already got my emergency-caffeine-and-regret playlist queued up for the "upgrade" weekend. Let's talk about what these beautiful charts actually mean for those of us who carry the pager.
First, let's toast the headline achievement: "the arrival rate of performance regressions has mostly stopped." This is like a pilot announcing, "Good news, passengers, we've stopped losing altitude as quickly as we were a minute ago!" The fact that we're celebrating a 30-40% performance drop on basic queries from an eight-year-old version as a "stable baseline" is justā¦ chef's kiss. We're spending money on new hardware to run new software that performs worse than the stuff we're already trying to get rid of. Ah yes, progress!
Your pristine sysbench setup on a freshly compiled binary is adorable. Really. But my production environment isn't 8 tables with 10M rows. It's a glorious, tangled mess of 1,200 tables created over a decade by developers who thought "index" was a chapter in a book. This benchmark completely ignores the real-world chaos of a query planner that's seen things you people wouldn't believe. I can already hear the marketing slides:
"Our new version excels in high-concurrency workloads!" ...and I can already see the reality at 3 AM on Memorial Day weekend when our main application, which is single-threaded and built on a framework from 2012, grinds to a halt because its simple point queries are suddenly 30% slower.
I see you've meticulously documented vmstat and iostat to explain why everything is slower. That's fantastic. You know what metric you forgot? TTM. "Time-to-Migrate-My-Monitoring." I guarantee that the internal counters and status variables our entire alerting infrastructure is built upon have been renamed, deprecated, or now calculate things in a slightly-but-catastrophically-different way. So while you're admiring the "reduced mutex contention," I'll be blind, trying to figure out why all my dashboards are screaming NO_DATA an hour after the zero-downtime migration.
The absolute best part is the write performance summary. On a small serverāyou know, like the dozens of auxiliary services we runāwrites are 40% to 50% slower on modern MySQL. But on the big, expensive server, they're faster! This is a brilliant business strategy: introduce so much new CPU overhead that customers are forced to triple their hardware spend just to get back to the performance they had on version 5.6. Itās not a bug, itās an upsell.
Honestly, all this "progress" just reminds me of the promises from other databases whose stickers now decorate my old laptop lid like tombstones. I'll add the MySQL 9.5 sticker right between my ones for RethinkDB and Aerospike's "free" edition. It's always the same story: revolutionary new features, a bunch of exciting benchmarks, and a fine print of performance regressions that I get to discover during a production outage.
Anyway, thanks for the charts. Iāll go ahead and pre-write the incident post-mortem.