This is a valid criticism of the methodology / explanation. It's not about the results. You can agree with the positive results (and they're great! - you've done awesome work and clearly show an improvement) and still say the explanation how/why they were achieved is not great.

Exactly. Immediately from the premise of the paper, I was looking forward to a discussion on how they tried various strategies to tune their JVM/GC parameters and found nothing. The "well I guess we gotta replace this with a C++ solution" sentiment smacks of poor software engineering practice, despite the results.

That you didn't find it, doesn't mean they didn't do any. Maybe it wasn't worth mentioning. Maybe they wanted to keep the post short. Some team successfully did a storage engine transplant and you're saying they're doing poor engineering?

That's definitely not what I was suggesting in my comment.

> The "well I guess we gotta replace this with a C++ solution" sentiment smacks of poor software engineering practice, despite the results.

On the flip side, recognizing when you are not efficiently using your time to solve a problem with the current approach and deciding to switch to another one is what I would consider a vital part of good software engineering, and also one of the hardest things to become good at without a lot of experience.

I'm not sure that's the case here, but I don't doubt it's possible they could easily have wasted more time testing and tweaking Java than it took to implement this solution. Whether that's how it would have (or possible even did to a degree) played out is an open question.

Good memory management is important for a high performance, low latency DBMS. I don't see how getting rid of GC is bad engineering practice. If a tool is not well suited for a problem, use another tool. Could you please explain your opinion?

//Edit: removed 2nd part, which wasn't really that important anyway...

That might be an argument for not using Cassandra. It’s a pretty big leap to reimpmenting half of Cassandra in c++.