Every time I start doing some network packet-based troubleshooting, for example firing up tcpdump to debug a tcp window size improperly tuned that caused a performance degradation over a high latency link (this is a random example I did last week), coworkers look at me like I pulled off some sort of wizardry. I feel it’s knowledge that most SWEs working on distributed systems should have acquired early and routinely use, but clearly that’s not the case.

Deeper internal knowledge of WebSockets and HTTP got me my current job.

> knowing that Postgres FK doesn't implicitly create an index.

Damn really lol

What does it do then, just block "breaking" deletes?

You can cascade the deletes in db layer rather than in app layer