6 ms·

So 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,

• eunos 8mo ago
  > 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.
  • LandR 8mo ago
    The point isnt to give a simple answer, even if it's a correct answer. The point is show how much you know and how smart you are. The question is framed to you as a way for you to show you know x, y and z and talk about x, y and z. Even if a valid solution is just do a, that's great. But the interviewer has no idea if you actually know about x ,y and z do they ?
    • lucianbr 8mo ago
      > The point is show how much you know and how smart you are. I like that this sentence can be read both as a productive, well-meaning view on interviews, as well as a highly cynical one. Also makes me wonder if the person will keep showing how much they know and how smart they are after they are hired, and if that is a good thing.
  • Aurornis 8mo ago
    In an interview you need to explain your thought process and demonstrate that you’re making an informed decision with supporting evidence. Saying “just use Postgres” and then providing no explanation for why you believe Postgres is sufficient for the job, a general explanation of what type of hardware and architecture you’d use, and other details is not answering the question.
  • praptak 8mo ago
    The point is the interviewers are sometimes obtuse. Sometimes the point of the interview is to see if the candidate knows an existing solution and "just use postgres" is the good answer. Sometimes it's to test the technical chops and pretending postgres doesn't exist is the point. The candidate shouldn't be expected to always guess right, unless the position says "a psychic". The interviewer should notice if the candidate is solving the wrong kind of problem and nudge them in the right direction instead of punishing the candidate for the wrong guess.
• Folcon 8mo ago
  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?
  • wreath 8mo ago
    I dont even think you need to be neurodivergent or anything to answer this question like the parent’s cofounder did. From one side, we call ourselves problem solvers, on the other hand we are not satisfied with simple solutions to these problems. If im interviewing for a job, i should be expected to behave and solve hypothetical problems the way id do it on the job. If that screws up your script, you probably suck at hiring and communicating your expectations.
    • johnnyanmac 8mo ago
      We also aren't mind readers and interviews are a crapshoot. Some companies do in fact want you leveraging tools and API's in your solutions. Some want to probe your foundational technical knowledge. Ideally they will poke you towards the answer they want, but not always. But few will let you know ahead of time for some reason.
  • wongarsu 8mo ago
    Or just add a couple zeros to all the requirements until postgres is a worse solution than whatever the interviewer envisions. Isn't that the point of stating throughput requirements?
    • wpietri 8mo ago
      Right? I'll often structure interview questions like this. I give a basic problem, hoping for a basic answer. Then I add complexity, seeing how they respond. In my experience, it's much easier to train somebody on how to scale a basic system up in response to need than it is to get somebody who favors complexity to cut it back.
• smallnix 8mo ago
  > 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.
  • jkubicek 8mo ago
    No, the point was to demonstrate how you’d design a complex system. If a valid answer was “just use Postgres” then it just wasn’t a very good interview question. In real life, the answer almost certainly would be “just use Postgres” and everyone would be happy.
    • chrisandchris 8mo ago
      No, it was a perfectly fine question IMHO. it is a broken incentive - it is expected that you design complex systems regardless whether they are useful or not. Try to interview for the role you have to fill, nor for a role you a dreaming you would love to have whenever you're Google2. If the interview wants you to think about stuff that never happens in your role, I think it is a sign that in your role, you're expected to solve the problems like in the interview.
• badosu 8mo ago
  Sorry, I didn't get it. What was the 'right' answer?
  • koakuma-chan 8mo ago
    distributed virtual abstract factory
    • tracker1 8mo ago
      You need the StrategyFactory in case you need further variances to the Factories you're making. https://github.com/EnterpriseQualityCoding/FizzBuzzEnterpriseEdition https://github.com/EnterpriseQualityCoding/FizzBuzzEnterpris...
  • wccrawford 8mo ago
    "Postgres, because..." They want a conversation to see how you think, not an actual answer. Which is stupid, because they asked a question that the person didn't need to think to answer. So they didn't get to see them think.
    • deleted 8mo ago
      [deleted]
  • sejje 8mo ago
    nosql on serverless
  • munchbunny 8mo ago
    It depends on the situation. Sometimes you just have a bad interviewer who is looking for something specific from you but isn't telling you. If you're experienced in these interviews, you catch the signs and adapt by asking questions to suss out which direction the interviewer wants to take it. Sometimes your answer is plausible but the interviewer wants to see you justify it. Sometimes your answer is wrong but the interviewer wants to see if you can reason your way through it, and maybe come up with an alternative. If you're junior/inexperienced, it's often hard to tell and it'll feel arbitrary/unfair, and unfortunately that's just how it goes. As a more senior/experienced candidate, you can often figure out which situation you're in by asking questions to feel out the interviewer and then try to pivot during the interview, though it still takes valuable minutes out of the interview that you could have otherwise spent showing your competence.
• wongarsu 8mo ago
  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
  • Aurornis 8mo ago
    Postgres might have been a perfect answer, but the candidate needs to explain why and how. The purpose of the interview is for the candidate to demonstrate their thought process and ability to communicate it. “Just use Postgres” doesn’t do that. This would be more obvious if it was a LeetCode problem and the candidate just regurgitated an algorithm from memory without explaining anything about it. Yeah it’s technically the right answer but the interviewer can’t tell if you actually understand what you’re talking about or if you just happened to memorize and answer that works. Interviews are about communication and demonstrating thought process.
    • wadadadad 8mo ago
      100% interviews are about communication and demonstrating thought process; after going through some rounds of interviewing candidates myself, any candidate who can adequately explain what they're thinking and how they arrive at their conclusions will be able to demonstrate their skills much more thoroughly than 'just use Postgres'. That being said, it's also on the ones giving the interviews to push the candidates and ensure that they really are receiving the applicants best. The interviewers don't want to miss potentially great candidates (interviews are hard and nerve-wracking, and engineers aren't known for their social performance), and thus sometimes need to help nudge the candidates in the right direction.
      • Aurornis 8mo ago
        Fully agreed on the point that interviewers should prompt and push candidates in the right direction. The best thing someone can do to learn how to perform well in interviews is to sit on the other side where you’re interviewing candidates. Some candidates will get stuck on arguing some irrelevant point or trying to fight against the interview question for too long in an interview. Once you see how much it hurts the interview process you learn to never do it yourself.
• MrBuddyCasino 8mo 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.
  • PKop 8mo ago
    Eh, it's a good answer and shows good instincts, but they still want to know how he would design a system if one was necessary. There's no need to be ridiculous about any of this from either perspective, which is why it should never have been a "fail" without the original interviewer simply saying "That's a solid answer now tell me what you would do if you had to build something new". I mean look how much time he wasted for everyone including his own CEO by being stubborn about it.
    • MrBuddyCasino 8mo ago
      If the numbers can be satisfied by a Postgres then thats the correct answer. The interviewers fucked up, because they sized the problem wrongly. This is the same issue that was prevalent when the industry switched from HDD to SSD: some system design questions suddenly became trivial, because the IOPS went up by magnitudes. This is not a failure of the interviewees, who correctly went with the times, but a failure of the interviewers.
      • LPisGood 8mo ago
        What kinds of system design questions got destroyed?
      • danenania 8mo ago
        The correct answer is “Postgres would handle it, but if it needed to scale even higher, I’d…” The point of a system design interview is to have a discussion that examines possibilities and tradeoffs.
        • 8mo ago
• PKop 8mo ago
  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.)
• eptcyka 8mo ago
  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.
  • lo_zamoyski 8mo ago
    On the one hand, interviewers can suck. They can be uninterested in understanding and embrace instead the role of a trigger-happy interrogator looking not for a good response - something that may very well require effort and considering new ideas on the part of the interviewer - but an excuse to cross you off the list. The interview begins to look like a game of "Guess what I'm thinking". Interviews should simulate a colleague asking you for help. On the other hand, interviewees can give poor answers with no explanation. The interviewer should press for an explanation in those cases, of course, but perhaps some are trying to see if the interviewee instinctively provides at least some basic rationale behind the answer without having to be prodded each time, in which case it is a matter of communication habits and skills. Communication is essential, and it is under-emphasized and under-taught in so-called 'STEM' curricula.
• fatnoah 8mo ago
  > 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.
  • btilly 8mo ago
    To be fair, the simple answer is not so simple within Google. The issue is that Google achieves reliability by insisting on n+2/n+1. Globally your service is in at least 2 more data centers than is required for full load. In each region in at least 1 more data center than is required for full load. If you're using the Google toolchain, all of the scalability and fallover problems are automatically handled by the layers that you're relying on. Which everyone expects you to use, because they are already integrated into the environment. But if you go to use Postgres as a data storage layer, then you also need to take care of replication, failover, backup, and make sure that this is integrated with the automated systems that Google already has to detect when this is needed. Even after you've done that, people from outside of your team will need to be convinced that you've done that. Simply because you're doing things differently, you'll get extra scrutiny. As a result, even if Postgres would have worked perfectly well, it is usually not the optimal answer for someone who is working within Google's environment. Don't think of it in terms of, "Does this do the job?" Think about it in terms of, "Can those in the broader organization easily certify that this does the job?" That certification is easier when you use standardized parts that are themselves already certified within the organization. My guess is that your interviewer was aware of this. And was left with, "What about that question that I didn't think to ask you about?"
    • dmurray 8mo ago
      If you're interviewing at Google, the expected answer to the interview question can't be to use Google's internal tools. "Use Postgres" is the standardized, understandable answer for anyone outside Google who needs to solve Postgres-shaped and Postgres-sized problems.
• renegade-otter 8mo ago
  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.
• anal_reactor 8mo ago
  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.
• Gooblebrai 8mo ago
  > 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?
  • coldtrait 8mo ago
    That was what I felt too. Why even need an interview for an acquihire when you have a direct link with the founder/CEO?
    • baobabKoodaa 8mo ago
      To maintain the illusion of meritocracy
• pjmlp 8mo ago
  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.
• marcosdumay 8mo ago
  Well, yes, doing the interview again is the right choice.
• flubijeq 8mo ago
  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.
  • getnormality 8mo ago
    Patrick Collison sounds like a lovely, trusting, scientifically-minded man who needs to learn the constructive power of destruction. The power of rage and contempt for bad solutions and bad communication (regardless of intent). With a smiley face front-end, of course. Wouldn't want to seem not-nice!
    • flubijeq 8mo ago
      Agreed, I really like Patrick - he is smart, humble, hardworking and trusting. But his kind and trusting nature is being aggressively exploited by some truly despicable people.
• yieldcrv 8mo ago
  “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
• twodave 8mo ago
  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.
• alistairSH 8mo ago
  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.
  • inaros 8mo ago
    That is why they say, as a candidate, you are also interviewing the company you would be working for...
• h3lp 8mo ago
  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"
• wpietri 8mo ago
  > 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?
  • wpietri 8mo ago
    Just to be clear, I'm absolutely not kidding here. E.g., this is the kind of hiring process I favor: https://williampietri.com/writing/2015/slightly-less-awful-hiring/ https://williampietri.com/writing/2015/slightly-less-awful-h... To rethink hiring, you have to spend some time understanding why most hiring is terrible both in terms of candidate experience and actual result. In my view so much of both hiring and general business operations is about managerial status and ego. https://en.wikipedia.org/wiki/The_purpose_of_a_system_is_what_it_does https://en.wikipedia.org/wiki/The_purpose_of_a_system_is_wha...
• bhk 8mo ago
  Let me guess: the point of the interview was to see if he was a "team player".
• kermatt 8mo ago
  They failed him because of that one question?