I doubt that anyone would claim their billing metrics are perfect. If you find some specific workload that's actually cheaper on another serverless database offering then we'd love to hear about it (we strive for transparent, generous pricing). If you don't think that CPU usage based pricing — which is typical for serverless offerings and e.g. is what Aurora serverless uses in Aurora Capacity Units (ACUs) — is charging you for reads of cached data then I've got some bad news for you. :-) You're almost certainly being charged for reading the "row" from the network, write-ahead-logging for it and other ACID/MVCC related overhead, writing it to block device, reading it from the block device, reading it from memory, writing it to memory, sorting and comparing [pieces of] it, and writing it back to the network — all of these things take CPU cycles. I find this argument to be entirely missing the point.

Pointing out that surely Amazon would like to keep their patch set to a minimum (there's a high cost in maintaining custom patches as you upgrade MySQL) is in no way implying that their patch set is small. Minimal means the minimum required for what you need, rather than being some point of pride.

I'm certainly not on here bashing any other offerings. Between the two of us, I only see one person trolling / bashing. :-) With that, I will leave you to your opinions which you are of course free to have. Best of luck.