alt Hacker NewsSo my cofounder was talking to Stripe about an acquihire (this was after I’d left.) As part of it, he had to do a systems design interview.
He got the prompt, asked questions about throughput requirements (etc.), and said, “okay, I’d put it all in Postgres.” He was correct! Postgres could more than handle the load.
He gets a call from Patrick Collison saying that he failed the interview and asking what happened. He explained himself, to which Patrick said, okay, well yes you might be right but you also understand what the point of the interview is.
They made him do it again and he passed.
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I feel like if that's the thought process, that should be stated up front
There's a ton of incredibly talented neurodivergent people in our ecosystem who would trip up on that question just because of how it's framed
Because how is the interviewee to know if you're testing for the technically sophisticated answer no one in their right mind would ever write or the pragmatic one?
> He got the prompt, asked questions about throughput requirements (etc.), and said, “okay, I’d put it all in Postgres.” He was correct! Postgres could more than handle the load.
I had this happen in a Google interview. I did back of the envelope math on data size and request volume and everything (4 million daily events, spread across a similar number of buckets) and very little was required beyond that to meet performance, reliability, and time/space complexity requirements. Most of the interview was the interviewer asking "what about" questions, me explaining how the simple design handled that, and the interviewer agreeing. I passed, but with "leans" vs. "strong" feedback.
This is just an indication that it's a poor interviewing technique. If you ask a question expecting the answer to be predictable then you had better cover all possible ambiguity in leading the candidate to the answer you want to hear. But then you're no longer asking the candidate to be creative, are you? As an interviewer I might be more inclined to allow such an answer and then follow up with questions of my own to test the limits of the candidate's knowledge of and confidence in Postgres as a technical choice for serving all the different constraints of the problem space. This way either I discover how well-reasoned the answer is or else (for a good candidate) it prompts them to adjust the design to better fit the problem. In no case would I expect they need to fit their answer into some key and then scold them for not playing along with my imaginary game.
> They made him do it again and he passed
I'd assume that if he got a call from Patrick himself and a second opportunity to get interviewed, that's already a cue for interviewers to pass him regardless of what he says?
If they don’t want to hear the correct answer, let them modify the question to exclude postgres answers. Interviews are a 2 way street, you will miss out on great candidates by being this stupid.
> you also understand what the point of the interview is
Exactly, it's also a test of ability to conform. Especially useful to weed out rogue behavior picked up in startups.
Great example, and a lost opportunity in the interview---they should have asked "What are the requirements that would invalidate this answer? and what would you design if the requirements were changed in this way?". Maybe even "how long is the runway for your Progress solution if we consider future scaling up of the requirements"
Let me guess: the point of the interview was to see if he was a "team player".
This is the part I would say thank you, and pass on the opportunity.
And yes, I have done this on a second Google interview about 15 years ago.
> They made him do it again and he passed.
I would hire the "just use postgres" dude in a heartbeat without re-testing, if the numbers made sense, and perhaps give a stern talking-to to the interviewers. But then again I'm not a unicorn founder, so what do I know.
Well, yes, doing the interview again is the right choice.
> okay, well yes you might be right but you also understand what the point of the interview is.
So the point is? I honestly dont understand.
I always find it funny that "engineers" straight out of school who barely know how to create a PR are expected to "ace" planet scale design questions. It's. Just. So. Dumb.
Completely idiotic on the part of the interviewer. Failing somebody for a correct answer - what a waste of everybody's time. If you want the candidate to pursue a particular technical path, tell them to do so while they're there in the office.
The best way to get promoted at stripe is just self-marketing and social manipulation. Good engineers are leaving meanwhile tecnical leadership is being replaced with designers and marketers. Internal performance metrics are heavily manipulated as well. Patrick has completely surrounded himself with extreme sycophants at this point - he has no idea what is actually going on in his company beyond curated metrics produced by manipulative sociopaths.
I realized that my manager really confuses complexity with robustness. Case in point: we have a very complicated script that runs at deployment time to determine the address of the database. It's been the source of a few incidents - database wasn't discovered because it was restarting and the script passed an empty string instead of stopping the deployment, script failed because of python update and empty configuration was passed, shit like that. I've been arguing "bro why can't we make terraform create a config file with all the addresses that is directly passed to the app at deployment, or better yet, just copy-paste the database addresses into a file in the repo because we change something there once a year at maximum" but my manager took it as a sign of incompetence and my inability to understand complex systems.
I feel like lots of people just follow the happy path and don't understand that complexity incurs real cost.
It's crazy the original interviewer allowed it to come to this which sounds like a waste of time for everyone involved, instead of simply saying; "Very good that is a legitimate solution to the problem. Now let's pretend you have to build something new, what would you do?"
Why on Earth did the company have to be so willingly obtuse and stupid about it including what sounds like the CEO (well at least he gave him another shot, but there doesn't need to be implicit assumptions about the "point of the interview", just come out and address it head on explicitly.)
“There’s no right answer we just want to see how you think” is gaslighting if there is a right answer and wrong answer.
This should go straight to the DOL, EEOC, FTC and other bodies as some form of abusive labor practice that excises it from the employment process under threat of economic sanctions
> yes you might be right but you also understand what the point of the interview is
To make the interviewer feel smart and powerful? To hire people who will do the thing the boss wants whether or not it makes sense? To find people who will overdesign things to maximize resume impact and the ability of their bosses to talk about what sophisticated systems they're running and for which they therefore need a much bigger budget?
If the point of the interview was to test if the candidate can design something that can handle google-scale problems then maybe the interviewer shouldn't state throughput and availability requirements that can be satisfied by postgres