Once we press the merge button, that code is no longer our responsibility. If it performs sub-optimally or has a bug, it is now the problem of the DevOps team, the SRE, etc. Unfortunately, those teams work with a different toolset. If my code uses up too much RAM, they will increase RAM. When the code runs slower, it will increase CPU. In case the code crashes, they will increase concurrent instances.
If none of that helps, they will call you up at 2 AM. A lot of these problems are visible before they become a disastrous middle-of-the-night call. Yes. DevOps should control production, but the information they gather from production is useful for all of us. This is at the core of developer observability, which is a subject I’m quite passionate about. I’m so excited about it I dedicated a chapter to it in my debugging book.