6 ms·

But what if Google is down and you are tasked with diagnosing it?

by gberger 10y ago

xigency 10y ago
Ask Jeeves? Being able to find it in a book might be useful, but when Google is down I bet they would like to get things up and running as soon as possible.
MaxfordAndSons 10y ago
I lost it at this one. As if there is some single point of failure that's going to bring all of Google down, and some intrepid director of engineering has to inspect some TCP packets by hand to fix it.
- ryandrake 10y ago
  This is where I threw up my hands too. The Director of Engineering does not need to know the difference between SIGTERM and SIGKILL, or how many bytes are in a MAC address. I guess it's a nice bonus if he does, but he'll spending 10 hours per day in meetings talking about roadmaps, shielding his team from the execs, and removing productivity roadblocks. "Third engineer from the left" is doing the packet inspection--ask HIM about SYN and ACK.
  - geofft 10y ago
    Reading more closely, it sounds like they are not interviewing him for a director of engineering position; it just sounds like he thinks his current role, CEO-who-writes-code of a very small software company (http://www.gwan.com/about http://www.gwan.com/about), qualifies him for a director-of-engineering-level position. He's probably being interviewed for an SRE team lead or thereabouts. Why he's being interviewed for that position is a different question entirely, and I can imagine Google being totally right or totally wrong.
    - btilly 10y ago
      How can you imagine Google being totally right here? The disconnect between the questions being asked and the interviewer's lack of knowledge made the interview a waste of time no matter WHAT role they are interviewing for. Take, for example, the sorting question. "Why is QuickSort the best sorting algorithm?" The answer being looked for was, "It has the best Big O." And this is wrong. Its average case is O(n log(n)). Its worst case is O(n^2). Which do you call its big-O? Moving on, the average case of O(n log(n)) is matched by a wide variety of sorting algorithms. How do you choose one? Here is a better answer. QuickSort is a very simple to implement algorithm which achieves the lowest average number of operations on a randomly sorted list. Which is why it is so widely adopted despite sometimes being very slow. However Timsort appears to be the fastest general purpose sorting algorithm for the mix of random and partially sorted lists seen in practice. When I tend to notice that sorting is slow, generally that's a larger workload where some type of merge sort would be appropriate.
      - geofft 10y ago
        I can imagine Google being totally right because I can imagine the interviewee not accurately remembering the conversation here. (I expect, for instance, that he did not write down the interview as it was happening.) In fact, conditioned on the assumption that Google is right that this guy's experience is better suited for SRE than director-level, it is pretty likely that he did not understand the questions being asked / thought the questions were beneath him / etc. and therefore wrote them down inaccurately. For instance, perhaps the interviewer asked "What makes quicksort a good sorting method," instead of "What makes quicksort the best sorting method"—a very small difference in phrasing. In that case, the answer of "It's not always the best, or even suitable" is still technically true, but much more wrong. (And an answer like the one you started with, "Its average case is O(n log (n)), its worst case is O(n^2)," would have been enough to pass... but sitting on the phone and arguing about storage topology is itself a failure.) As I mentioned in another comment https://news.ycombinator.com/item?id=12702130 https://news.ycombinator.com/item?id=12702130 , my (five-year-old, faulty) memory of Google's SRE phone interview is that they asked another question here with a very small but important phrasing difference: "What is the signal sent by the kill command" instead of "What is the kill signal". If you make that change, the interviewee's answer of "SIGKILL" becomes wrong, and the interviewer is right to insist on SIGTERM (which would otherwise make no sense). It is a quite literal game of telephone. (Again, I can also imagine Google being totally wrong and the interviewer mangling the questions.)
sgift 10y ago
Then you do what people did before Google when they didn't know some trivia: Use a book.
- deleted 10y ago
  [deleted]
aetherson 10y ago
If they are trying to hire for a position that will somehow be on the line for what happens when all of Google is down, I for real hope that they get some higher-power questions into that interview. But, obvs, the answer is that you Bing it.
- ionwake 10y ago
  This is the funniest thread I've ever seen on HN
gbjones 10y ago
Is that a trick question? Open APUE, ``apropos inode``, ...
teraflop 10y ago
I bet Google has their own internal "backup Google", for just such an occasion.
- dekhn 10y ago
  yes it's called "Stevens" https://www.amazon.com/TCP-Illustrated-Vol-Addison-Wesley-Professional/dp/0201633469 https://www.amazon.com/TCP-Illustrated-Vol-Addison-Wesley-Pr... although you might also check TAOCP.

But what if Google is down and you are tasked with diagnosing it?

by gberger 10y ago

But what if Google is down and you are tasked with diagnosing it?

Ask Jeeves? Being able to find it in a book might be useful, but when Google is down I bet they would like to get things up and running as soon as possible.

MaxfordAndSons 10y ago

I lost it at this one. As if there is some single point of failure that's going to bring all of Google down, and some intrepid director of engineering has to inspect some TCP packets by hand to fix it.

ryandrake 10y ago
This is where I threw up my hands too. The Director of Engineering does not need to know the difference between SIGTERM and SIGKILL, or how many bytes are in a MAC address. I guess it's a nice bonus if he does, but he'll spending 10 hours per day in meetings talking about roadmaps, shielding his team from the execs, and removing productivity roadblocks. "Third engineer from the left" is doing the packet inspection--ask HIM about SYN and ACK.
- geofft 10y ago
  Reading more closely, it sounds like they are not interviewing him for a director of engineering position; it just sounds like he thinks his current role, CEO-who-writes-code of a very small software company (http://www.gwan.com/about http://www.gwan.com/about), qualifies him for a director-of-engineering-level position. He's probably being interviewed for an SRE team lead or thereabouts. Why he's being interviewed for that position is a different question entirely, and I can imagine Google being totally right or totally wrong.
  - btilly 10y ago
    How can you imagine Google being totally right here? The disconnect between the questions being asked and the interviewer's lack of knowledge made the interview a waste of time no matter WHAT role they are interviewing for. Take, for example, the sorting question. "Why is QuickSort the best sorting algorithm?" The answer being looked for was, "It has the best Big O." And this is wrong. Its average case is O(n log(n)). Its worst case is O(n^2). Which do you call its big-O? Moving on, the average case of O(n log(n)) is matched by a wide variety of sorting algorithms. How do you choose one? Here is a better answer. QuickSort is a very simple to implement algorithm which achieves the lowest average number of operations on a randomly sorted list. Which is why it is so widely adopted despite sometimes being very slow. However Timsort appears to be the fastest general purpose sorting algorithm for the mix of random and partially sorted lists seen in practice. When I tend to notice that sorting is slow, generally that's a larger workload where some type of merge sort would be appropriate.
    - geofft 10y ago
      I can imagine Google being totally right because I can imagine the interviewee not accurately remembering the conversation here. (I expect, for instance, that he did not write down the interview as it was happening.) In fact, conditioned on the assumption that Google is right that this guy's experience is better suited for SRE than director-level, it is pretty likely that he did not understand the questions being asked / thought the questions were beneath him / etc. and therefore wrote them down inaccurately. For instance, perhaps the interviewer asked "What makes quicksort a good sorting method," instead of "What makes quicksort the best sorting method"—a very small difference in phrasing. In that case, the answer of "It's not always the best, or even suitable" is still technically true, but much more wrong. (And an answer like the one you started with, "Its average case is O(n log (n)), its worst case is O(n^2)," would have been enough to pass... but sitting on the phone and arguing about storage topology is itself a failure.) As I mentioned in another comment https://news.ycombinator.com/item?id=12702130 https://news.ycombinator.com/item?id=12702130 , my (five-year-old, faulty) memory of Google's SRE phone interview is that they asked another question here with a very small but important phrasing difference: "What is the signal sent by the kill command" instead of "What is the kill signal". If you make that change, the interviewee's answer of "SIGKILL" becomes wrong, and the interviewer is right to insist on SIGTERM (which would otherwise make no sense). It is a quite literal game of telephone. (Again, I can also imagine Google being totally wrong and the interviewer mangling the questions.)

sgift 10y ago

Then you do what people did before Google when they didn't know some trivia: Use a book.

deleted 10y ago
[deleted]

aetherson 10y ago

If they are trying to hire for a position that will somehow be on the line for what happens when all of Google is down, I for real hope that they get some higher-power questions into that interview. But, obvs, the answer is that you Bing it.

ionwake 10y ago
This is the funniest thread I've ever seen on HN

gbjones 10y ago

Is that a trick question? Open APUE, ``apropos inode``, ...

teraflop 10y ago

I bet Google has their own internal "backup Google", for just such an occasion.

dekhn 10y ago
yes it's called "Stevens" https://www.amazon.com/TCP-Illustrated-Vol-Addison-Wesley-Professional/dp/0201633469 https://www.amazon.com/TCP-Illustrated-Vol-Addison-Wesley-Pr... although you might also check TAOCP.