[levosmetalo]

I remember my interview at Spotify where we discussed how to implement thumbnail display service in the most effective way. What we actually came to is something along the lines of this library.

I always like it when a company focus on their real problems in job interviews and manage to avoid the brain teaser trap. That way you can have a feeling about the job that you are going to work on there, and see if you really like both work and people.

[rohansingh]

Thanks :-) That is a go-to interview question for us and we actually all do it slightly differently and take it in different directions depending on your expertise or specialization.

It is really closely aligned to what our core service is (distributing and streaming files) and is a great chance to talk with the interviewee and figure out where their strengths are.

Totally encourage other people to interview this way. It's what I've done at the past few companies I've been at and really worked excellently — just think of a problem you're working or have worked on, and distill it into an interview problem.

[staunch]

I also like this style, but you have to be very mindful of the fact that you've been thinking about the problem 1000x more than the candidate. The Curse of Knowledge[1] haunts the interview process. I haven't tried it much, but maybe it would be better to always use a fresh problem in each interview that not even you had seen. Maybe selected from StackOverflow.

1. http://en.m.wikipedia.org/wiki/Curse_of_knowledge

[jetz]

If you're familiar with thumbnail display you know Facebook has Haystack for efficient image serving. It goes very low end. Sparkey or CDB or BAM (mentioned in this post) could be much less complex and can do similar work. Why did they go Haystack route I dont get it.

[seiji]

Are you asking why they didn't use Haystack? Haystack isn't released publicly as far as I can tell (plus, just because another company writes something doesn't mean it's actually good).

[jeltz]

No, I think he is asking why Facebook isn't using something like CDB.

[jetz]

Sorry not being clear enough. Yes I was kind of asking why they didnt try simpler options. When you look at their paper on Haystack you see that it's essentially a constant local database.