I’m not usually one to complain about AI being used to generate content because I find this and especially interesting topic, but it really took me out of it.
More relevant to the topic at hand, I feel like I didn’t put that much thought into designing my interview questions, but I’m always astounded when I read these sorts of descriptions of other interview questions. There should perhaps be some formal training or certification or something for asking good engineering interview questions.
There was one person on this site who looked down at candidates (for a normal software development job) who didn't answer his interview question well. And by well, I don't mean being curious and working it out on the fly, I mean that if the candidate didn't know the answer of the top off their head, the HN commenter deemed them uncurious and unsuitable. The question?
The best interview question to find great developers is this:
"What number am I thinking of?"
Smart developers - really smart developers are always right. Truly great developers have seen this sort of problem before and know how to attack it - they need no fancy questions or "deeper understanding". They simply hit the whiteboard, do the logic and output the answer.
The solution to this entirely depends on whether you are willing to answer other questions about the number and of what nature. Would you answer: is it higher/lower than X? How about how many digits there are?
But assuming you are unwilling to answer any additional questions, the correct solution is to simply brute force every number up from 0 and its negative.
I don't think this is a good interview question, but I do think it is interesting as a thought exercise.
I bet that perhaps 25% of candidates could actually answer the question correctly, even if they didn't know anything about Schelling points. It could also lead to some nice discussions about how to solve an open-ended problem, probability distributions, strategies for maximizing payoffs when making decisions in the face of uncertainty, and so on. The question is so bad, it's actually kind of good.
I think it’s a great interview question. Open-ended, rewlly leads to a good discussion that can give you a sense of how the applicant approaches a problem and thinks it through.
Disastrous in the hands of an interviewer who’s looking for a one word answer.
At a job interview in 2016, I was given a fairly typical "design Twitter" whiteboard problem, so I started doing a fairly typical thing involving load balancers and Nginx and the like.
The topic of the database came up, and I asked "Do we care more about consistency or availability?".
He responded back with "we want both".
I said "I mean, I would like both too but I'm pretty sure we can only get one"
He disagreed and we went back and forth, and eventually I pull out my phone and pull up the Wikipedia for CAP theorem. He eventually (and begrudgingly) agreed and said "umm, I guess availability", so I used Cassandra and moved on with it, though five minutes were wasted with this pointless argument.
To be fair, they did make me an offer, and it was even a decent enough offer (though I ended up taking a different job), but I remember being kind of flabbergasted that I had to explain CAP theorem to a person who had like a decade more experience than I did. It's not like CAP theorem is this super deep arcane topic; I'm pretty sure it's one of the first things you learn about when getting into distributed systems. It was certainly one of the first thing that I learned about.
The interviewer question was adversarial... don't think it puts them in a good light.
More importantly I appreciate the OP for describing lessons learned through this hard experience. I worked in finance: Cassandra is no kind of answer for systems of record
> Not because it’s trendy. Because ACID compliance
> The CAP theorem is not a suggestion. It’s a mathematical proof.
> this is not a philosophical inconvenience. It’s a compliance violation.
@dang, i thought we just banned AI written blog posts?
I know I will get downvoted for this everytime I post this comment, but I'm sick and tired of 80% of everything being written/heavily edited by AI.
Can the author not just use his own words? Is he really that bad at writing? But somehow the content is supposed to ne worth my time?
I'd rather read the prompt instead, so I know which parts the author actually meant to say, rather than wondering which parts the AI invented to make it sound flowery and punchy, the Tiktok style of prose.
I really appreciate that your response to being interviewed by an idiot is to write, not an angry rant, but an educational blog post. You are a good person and they didn't deserve you.
I feel this is misleading. I think a reasonable definition of a 'good' engineer is engineer in the 75th percentile and above for their craft. You can debate other definitions, I'm not saying this is the only reasonable one. But by this definition, I think you can immediately see that it is hard -- given 4 engineers, we expect that only one of them is "good". And what if your standards are higher? What if you only want _great_ engineers? I can't believe that it's easy.
It's hard because people are threatened by good people and don't want to hire them, and also objective standards leave less wiggle room to sneak in your friends or others in your peer group.
Many, many forces lined up against meritocracy. All the incumbents, for example, tend to have something to lose, but it's the incumbents who decide if you are hired.
It's a miracle that there are any good companies once the original owners are gone.
If anything it shows the applicant was over qualified and it probably wasn't a great fit; to have this guy, who has battle experience, in a place where the interviewer was looking for a one-size-fit-all canned type answer.
> The answer he was looking for was ‘Cassandra’. “You’d have a hard time having it NOT be resilient.”
A "database" that starts to fall if the ring in the cluster becomes choked? Draining a broken Cassandra ring and under high load is hell and ball clenching.
Especially hoping that another Cassandra node doesn't fail under high load. Pish, Erlang and mnesia.
I'm glad I read the "Designing Data Intensive Applications" book because I get the full context of the blog.
And the lesson of the blog is why forcing LLM usage is stressful to some engineers. Most implementations are in a quantum state and the back and forth to have clear requirements is what can make the wave function collapse. We know all the possible answers , but all of them are equally valid.
We could go with the LLM route and just do a quick guess on the answer, but "Accountability" and "Professionalism" prevent us from doing so.
More relevant to the topic at hand, I feel like I didn’t put that much thought into designing my interview questions, but I’m always astounded when I read these sorts of descriptions of other interview questions. There should perhaps be some formal training or certification or something for asking good engineering interview questions.
Use your own words! I'd rather read the prompt instead!
"How do mobile phone towers work?"
"What number am I thinking of?"
Smart developers - really smart developers are always right. Truly great developers have seen this sort of problem before and know how to attack it - they need no fancy questions or "deeper understanding". They simply hit the whiteboard, do the logic and output the answer.
Don't settle for anything except A players.
Same with your last sentence.
But assuming you are unwilling to answer any additional questions, the correct solution is to simply brute force every number up from 0 and its negative.
I don't think this is a good interview question, but I do think it is interesting as a thought exercise.
I bet that perhaps 25% of candidates could actually answer the question correctly, even if they didn't know anything about Schelling points. It could also lead to some nice discussions about how to solve an open-ended problem, probability distributions, strategies for maximizing payoffs when making decisions in the face of uncertainty, and so on. The question is so bad, it's actually kind of good.
Disastrous in the hands of an interviewer who’s looking for a one word answer.
The topic of the database came up, and I asked "Do we care more about consistency or availability?".
He responded back with "we want both".
I said "I mean, I would like both too but I'm pretty sure we can only get one"
He disagreed and we went back and forth, and eventually I pull out my phone and pull up the Wikipedia for CAP theorem. He eventually (and begrudgingly) agreed and said "umm, I guess availability", so I used Cassandra and moved on with it, though five minutes were wasted with this pointless argument.
To be fair, they did make me an offer, and it was even a decent enough offer (though I ended up taking a different job), but I remember being kind of flabbergasted that I had to explain CAP theorem to a person who had like a decade more experience than I did. It's not like CAP theorem is this super deep arcane topic; I'm pretty sure it's one of the first things you learn about when getting into distributed systems. It was certainly one of the first thing that I learned about.
More importantly I appreciate the OP for describing lessons learned through this hard experience. I worked in finance: Cassandra is no kind of answer for systems of record
Thanks
> The CAP theorem is not a suggestion. It’s a mathematical proof.
> this is not a philosophical inconvenience. It’s a compliance violation.
@dang, i thought we just banned AI written blog posts?
I know I will get downvoted for this everytime I post this comment, but I'm sick and tired of 80% of everything being written/heavily edited by AI.
Can the author not just use his own words? Is he really that bad at writing? But somehow the content is supposed to ne worth my time?
I'd rather read the prompt instead, so I know which parts the author actually meant to say, rather than wondering which parts the AI invented to make it sound flowery and punchy, the Tiktok style of prose.
Why does it require 30,000 servers to process millions of daily transactions? Is there a typo in the amount?
Sometimes you gotta fire your interviewer.
I feel this is misleading. I think a reasonable definition of a 'good' engineer is engineer in the 75th percentile and above for their craft. You can debate other definitions, I'm not saying this is the only reasonable one. But by this definition, I think you can immediately see that it is hard -- given 4 engineers, we expect that only one of them is "good". And what if your standards are higher? What if you only want _great_ engineers? I can't believe that it's easy.
1. Person who cares 2. Person who is knowledgeable 3. These two must be the same person!
Many, many forces lined up against meritocracy. All the incumbents, for example, tend to have something to lose, but it's the incumbents who decide if you are hired.
It's a miracle that there are any good companies once the original owners are gone.
naming "cassandra" is not designing a database.
it feels like there was some miscommunication along the way
You sweet summer child.
The things I've seen at certain worksites...
A "database" that starts to fall if the ring in the cluster becomes choked? Draining a broken Cassandra ring and under high load is hell and ball clenching.
Especially hoping that another Cassandra node doesn't fail under high load. Pish, Erlang and mnesia.
And the lesson of the blog is why forcing LLM usage is stressful to some engineers. Most implementations are in a quantum state and the back and forth to have clear requirements is what can make the wave function collapse. We know all the possible answers , but all of them are equally valid.
We could go with the LLM route and just do a quick guess on the answer, but "Accountability" and "Professionalism" prevent us from doing so.