MongoDB Interview Questions | Glassdoor

MongoDB Interview Questions

Updated Sep 27, 2017
123 Interview Reviews

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  1.  

    Software Engineering Interview

    Anonymous Employee in New York, NY
    Accepted Offer
    Positive Experience
    Difficult Interview

    Application

    I applied online. The process took 3 weeks. I interviewed at MongoDB (New York, NY) in October 2016.

    Interview

    The MongoDB interview process was great. I had a technical phone screen, two onsite technical interviews, and one onsite interview with a product manager.

    My recruiters were very friendly and I got to tour the office. They asked challenging questions in the technical interviews, and the engineers were very friendly. My product manager interview was literally with one of the chief architects, which was awesome pretty freaking awesome.


  2. Helpful (4)  

    Curriculum Engineer Interview

    Anonymous Interview Candidate
    No Offer
    Negative Experience
    Difficult Interview

    Application

    I applied online. The process took 2 weeks. I interviewed at MongoDB in March 2016.

    Interview

    Spoke with the first interviewer for 30 minutes over the phone. The conversation was friendly, but a bit one-sided, as I only was able to ask him about one minute of questions during the entire phone call. He then asked me to email him questions I had about the job, and I did, but he took 9 days to respond to them. What is even more concerning is that one of the questions I asked via email was "What is the most important thing you feel is necessary to be a good manager" and he replied "responsiveness". After reading that answer, I unfortunately had to take everything else he said with a grain of salt.

    The following week, I did a one-hour technical interview with a second interviewer where I typed code into a text editor while the interviewer watched and asked me questions. The technical interview seemed more like a Software Engineering interview, as I was required to build fairly complex programs from scratch in front of the interviewer, which seemed a bit inappropriate for a Curriculum Developer interview and seemed a bit too academic as well. The company should probably modify the interview process where code samples with typos/errors could be presented to the job candidate and then the candidate could try to find the typos/errors. Or, the candidate could tell the interviewer what the output of a certain algorithm would be.

    Those interested in the job should also keep the following in mind:

    1.
    The company is going to promote a new manager by September 2016, so the current manager will most likely "not" be your boss for long.

    2.
    The department is dominated by former college professors and researchers, so you will need to be comfortable working inside a very "academic" culture.

    3.
    According to the interviewer, you are expected to work 50-60 hours per week in this role.

    Interview Questions

    • Find the most repeated character in string of random characters   Answer Question
    • take an array of sorted numbers and return each number squared and sorted. Be sure to account for negative numbers.   Answer Question
    • How would you create a method/way to determine how to know if a person is likely to answer a test question correctly.   Answer Question
    • Semaphore vs Mutex; Process vs Thread; Vector vs Linked List; What make an algorithm efficient? How would you build a curriculum to educate people about lobsters?   Answer Question
    • return files in a folder that contain the number "100" in the filename using linux commands; return text files in a folder that contain the number "100" in the text body using linux commands   Answer Question
  3.  

    Solutions Architect Interview

    Anonymous Employee in New York, NY
    Accepted Offer
    Negative Experience
    Difficult Interview

    Application

    I applied through a recruiter. The process took 3 weeks. I interviewed at MongoDB (New York, NY) in November 2012.

    Interview

    The interview process is extensive. It can be daunting and it can be exhausting. Some interviewers will be "adversarial" and they will attempt to see how you perform under pressure. I know several folks who are extremely talented but did not get an offer. The interview process will eliminate some good candidates, but everybody who eventually gets an offer is at the top of their field.

    Interview Questions

    • Question about best practices for a specific programming language? Or how different programming languages differ   Answer Question

  4.  

    Technical Services Engineer Interview

    Anonymous Employee in Gurgaon, Haryana (India)
    Accepted Offer
    Positive Experience
    Difficult Interview

    Application

    I applied online. I interviewed at MongoDB (Gurgaon, Haryana (India)) in September 2015.

    Interview

    - There are many rounds of interviews and it may vary from candidate to candidate
    - Starts with what you do and why you want to be here
    - You can drive the interview and focus on the skills that you are good at
    - The job requires wide variety of skills and thus no single skill is good over another (depends on the interviewer perception)
    - Mix skills of linux, databases, networking, software development etc.

    Interview Questions

    • A part of the customer's application is not doing well. What is your approach to troubleshoot?   1 Answer

  5.  

    Accepted Offer
    Positive Experience
    Difficult Interview

    Application

    I applied through a recruiter. I interviewed at MongoDB in October 2016.

    Interview

    I was reached out to through Piazza by a university recruiter, and after an initial behavioral phone screen, began the interview process. There was a single technical interview through a shared coding platform, and then I was invited to final rounds. Because of my busy school schedule I conducted the final round via BlueJeans and a coder-pad-esque shared code-editor. It consisted of three rounds of technical interviews and a final behavioral round with one of the VP of engineering's at mongodb. The whole process was well organize, quick and in all, a wonderful experience!

    Interview Questions


  6. Helpful (7)  

    Technical Services Engineer Interview

    Anonymous Interview Candidate in Austin, TX
    No Offer
    Negative Experience
    Difficult Interview

    Application

    I applied through a recruiter. The process took 2 weeks. I interviewed at MongoDB (Austin, TX) in January 2017.

    Interview

    I was contacted by a recruiter who submitted my resume to the HR department. In my process I had 2 phone interviews followed by an on site interview. Both phone interviews were 30 minutes. The onsite interview was 4 hours.

    The interview process covers a lot of things. OS concepts, hardware, Linux, networking, disk configurations, high availability and databases. This is a database company, but your resume or database skills will not give you the job.

    Interview Questions

    • The first thing that you have to understand is that MongoDB is trying to find the "best of the best". Therefore the interview goes into disqualification mode. Another interesting thing is that even when this is a "database" product, that doesn't mean that they are looking for people with database skills, my impression is that they would take anyone with strong Linux and storage background. In addition, every interview is different and as matter of fact they track every single question into their system and hence they know exactly what they have asked and what needs to be asked in the next interview.

      Questions in my first phone interview:

      - What is an index?
      - What are the benefits/downsides of an index?
      - What is a compound index?
      - How to resolve the Intersection of the list? In a database world, this is the equivalent of a join. The easy answer would be a nested loop.
      - Questions about raids. (Rad 1, Raid 5, Raid 10).
      - Other types of db questions like What is a correlated query?

      Second phone interview:

      - What is a virtual function?
      - What is a template?
      - How do you implement virtual functions in C?
      - Scenario Question: I have deployed a new application and it has performance issues, how do I troubleshoot it?
      - Scenario Question: What happens when you submit a query to the database? (query parsing process)

      First onsite interview.

      - The interview was a web meeting and it was 2 person panel. In this interview both guys are asking questions at the same time.
      - Scenario questions: We have 2 systems, everything is the same, one system is performing fine and the other is executing queries slower, how do you approach this problem?
      - How do you change kernel parameters?
      - Can you explain in detail how swap space work?
      - What happen if you have an application of 8 GB and you only have 4GB of physical memory?
      - Provide an example of one of the most complex issues you have resolved.

      Second onsite interview:

      - What information is need in order to configure the network settings in a computer?
      - What is TCP?
      - What is UDP?
      - Provide examples of applications using UDP / TCP
      - Questions about network services like DHCP, DNS.
      - Utilities to monitor performance in Linux.
      - Explain RAIDs.
      - If you have RAID 5, how much space can be actually used? Does it change if you add more disks?
      - What utilities do you use to monitor performance of the operating system?
      - Scenario question: How do you troubleshoot a connection issue between an application and a database server?

      Third onsite interview:

      This guy only asked one question:

      "Can you design a system to store a PB of information?"

       You have to put attention to the following components:

      - What type of HW are you going to use?
      - How are you going to store the actual data?
      - Details about cluster configuration, what if the heartbeat fails but it is a false positive?
      - Do you replicate the information? how? and how long would it take if one node fails?
      - Be ready to do quick calculations. For instance, if you said you have an internal network of 1 Gbit per second, how long would it take to transfer 1 TB?
      - The solution has to be designed in a way that it can grown in a horizontal way.

      Tips:
      - You have to convince the interviewer that you want to work for Mongodb because you really like the technology and not just because it is a nice company.
      - The interviewer also expects some type of level of knowledge about MongoDB and how it is been used by the customers.
      - Your answer has to be complete, give as much detail as possible.
      - You have to know what you are responding. For instance, if you said "You can use vmstat to monitor cpu, memory and swap space", a follow-up question would be "Can you tell me what information vmstat is giving you about the swap space? is it in pages, blocks or MB?
      - Google known issues with MongoDB and Linux. They can be used as example in your answers.   Answer Question

  7.  

    Solutions Architect Interview

    Anonymous Interview Candidate in London, England (UK)
    No Offer
    Negative Experience
    Difficult Interview

    Application

    I applied online. The process took 3+ months. I interviewed at MongoDB (London, England (UK)) in January 2017.

    Interview

    I had the following process:
    1. HR screening
    2. Hiring manager
    3. Technical/SA interview
    4. US VP of Sales interview
    5. Low level sales person interview
    6. "VP" Sales interview

    What started off as a bright start was soured at the end by an arrogant sales team. I interviewed with the SA and Tech side of the team which got my excited about potentially working for MongoDB, they seemed smart and driven which was then compounded by meeting the US VP of Sales.
    I should state I went above and beyond most candidates by taking time out of my current job and work trip to NYC to accommodate an interview with him as did he. He is really nice and very respectful, shame the UK team don't take lead from him.

    What they don't tell you when interviewing for the UK office is that whilst they claim it's a committee decision for hiring, it's basically down the VP of Northern Europe and Belux that decides and if he doesn't like or rate you then all the other months of interviewing are irrelevant which as a candidate is frustrating.

    On that note their sales team is unprofessional, both times I interviewed they were late. On the 6th interview they showed up 30 mins late. I'm sure they wouldn't have appreciated it if I showed up 30 mins late and still expected to interview. Their disrespect for candidates was clear when they didn't even apologise for their tardiness.

    Beware if you are interviewing towards the 5th and 6th interview, they ask illegal questions such as age and personal questions about your background that are irrelevant to your ability to perform a job. Also their interview technique is basically intimidating you and then claiming it's about pressure based when the reality is that their questions are subjective and the answers they are looking for are purely based off them thinking their opinion is the only correct opinion.

    Overall it's a shame as MongoDB is a decent product with a bright future but on some thorough reflection I actually feel like I've dodged a bullet due to having to work with a uncharismatic sales team with zero humility and a SA manager with no backbone to fight for what he wants due to being scared of the sales team.

    Oh the last thing to note, expect to talk about your CV as not a single one of them made an effort to pre-read it before the interview and then had the audacity to tell me off for not researching the CEO. Let me be clear on the last part, the CEO not the company, the CEO. Whilst I agree it's important to do full research that I personally didn't get to do, knowing what the CEO writes on the MongoDB blog has no bearing ones ability to do a job.

    As someone who conducts interviews myself I just found the sales team overall technique odd. It's like they've been taught a specific way to conduct interview and if the answer isn't on that approved list then it's wrong in their eyes.

    Interview Questions

    MongoDB Response

    Apr 17, 2017 – CEO

    Thank you for sharing this. Our rigorous interview process is not an excuse for any current employee to be anything less than respectful. Everyone in our organization should make sure every guest... More

  8. Helpful (1)  

    Corporate Account Executive Interview

    Anonymous Interview Candidate in Austin, TX
    No Offer
    Negative Experience
    Difficult Interview

    Application

    I applied through a recruiter. The process took 2+ months. I interviewed at MongoDB (Austin, TX) in January 2017.

    Interview

    I was contacted by a recruiter for this position. Had a handful of phone interviews, then was invited to an onsite interview. Spent 3 hrs interviewing with 2 Sales directors and the VP of Corporate sales. I thought it went well. I was invited back for their "challenge" portion of the interview. Which is a 1 hr role play of a sales meeting. This takes a good amount of time to prepare and research for. I was told if you make it this far it is a 90% done deal you will get hired. They liked my challenge and gave some feed back, then asked if I could do another role play to see how I took their feed back.

    This 2nd role play was canceled 5 mins after it should have started. I almost backed out at this point due to them being unprofessional and already canceling several calls last minute. The recruiter talked me into sticking it out. So I proceeded to do the 2nd role play interview with both Sales directors out of the Austin office. I was then told I did a great job and they would pass on their recommendation to hire me to the VP of Sales.

    At this time I was given a verbal offer, walked through what my comp plan would be, as well as stock options, as well as other things. We talked about when I would be available to start.

    I was then contacted and told I needed to have a call with the CRO (Chief Revenue Officer). After him canceling our meeting 3 times, I finally was able to have a brief 25 min conversation with him. Very high level about my background. Where I grew up, went to school, career path to this point, etc.

    2 Days later I received a call from the sales director informing me they would not be hiring me. This comes after almost a 2 month process, a total of 4 hours of in person interviewing, Countless phone calls, many of which were canceled last minute and rescheduled.

    I currently have a job, and put in a ton of time and even took time off of work to pursue this, because I was told countless times how much they liked me and wanted me on the team. Only to be told I wasn't the right fit after being drug through their VERY unprofessional process.

    Ended up being an epic waste of time and left a very bad taste in my mouth as to the professionalism of this organization.

    Interview Questions

    • They do a fairly in depth role play where you select a company and have to conduct a sales meeting/pitch of the Mongo product.   Answer Question

  9.  

    Account Executive Interview

    Anonymous Employee in New York, NY
    Accepted Offer
    Positive Experience
    Difficult Interview

    Application

    I applied through other source. The process took 4 weeks. I interviewed at MongoDB (New York, NY) in December 2016.

    Interview

    As far as most AE interviews go, this was pretty on par. I spoke with the team's director a few times before meeting him in person and then moving on to a call with the global head of corporate sales.

    Upon learning that I had qualified for the next round, I came in for a group setting interview and gave a presentation. Fairly painless process, though there is some pressure given that I came from outside of the database industry. Everyone was extremely nice, gave thoughtful/honest feedback, and were reachable in case I had questions.

    Interview Questions


  10.  

    Intern Interview

    Anonymous Interview Candidate in Austin, TX
    No Offer
    Positive Experience
    Difficult Interview

    Application

    I applied online. The process took 4+ weeks. I interviewed at MongoDB (Austin, TX) in November 2016.

    Interview

    I applied online a month or two ago and was emailed by a recruiter to set up a phone screen. The recruiter asked some behavioral and semi-technical questions - not too hard. Next, there was a technical phone screen interview; there were general data structures and algorithm questions.

    There were three interviewers in the final round interviews. The first was technical, but more focused on problem solving and data structures knowledge. The second was behavioral, probably to determine if I was a cultural fit. The third one was technical and had an online coding challenge.

    Interview Questions

    • Implement DFS/BFS for a binary search tree.   Answer Question
    • You are given a histogram plot. If rain "falls" on top of the histogram plot and gets trapped in between the bars, what is the area of the trapped rain water?   Answer Question
    • How do you balance a binary tree without using a self-balancing algorithm like the ones Red-Black Trees and AVL trees use?   Answer Question

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