from Hacker News

Ask HN: What engineering trivia earned you the most cred

by porkbrain on 5/7/25, 5:48 PM with 4 comments

Is there a specific piece of engineering knowledge that powered you to substantially contribute?

A software engineering example: knowing that Postgres FK doesn't implicitly create an index. Three different projects I joined weren't aware of this and we managed to improve the performance with a negligible amount of effort.

Keen to hear your wins (and make them mine ^^

  • by deanmoriarty on 5/8/25, 2:19 PM

    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.

  • by austin-cheney on 5/8/25, 9:38 AM

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

  • by catlover76 on 5/7/25, 5:49 PM

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

    Damn really lol

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