Oracle OCI | IC3 | India |

I recently interviewed at Oracle OCI for an IC3 position. I was selected in February , but unfortunately, due to a hiring freeze, my offer letter was never released. I have since given up on OCI and am writing my interview experience here.

• Technical Screening Round (In-Depth):

  • Leetcode problem: Longest Substring Without Repeating Characters

  • Where do you mention environment changes in the Helm chart?

  • You have a table, write a query to output day-wise total sales.

      **select sum(amount) from sales group by sale_date LIMIT 2**
    

  • How does a migration file look like inside?

    • How to modify a migration file such that a few rows contain one set of default values and a few other rows contain another default value?
    • How do migration dependencies work... for example, for the 006_ini file, will only the 005 dependency be there or will 001, 002, 003, 004 all be there? (Answer: Only 005 will be there.)

  • How do you write an endpoint for an email service?

  • How do you do load balancing... which algorithm?

  • Write a cron job syntax: 0 * * * *

  • What states did you use in React? Write the syntax for useState and how do you update the state?

  • Difference between props and state?

  • How do you access a DOM element in React?

  • Write an onClick function.

  • Write a promise.

  • Write an Axios POST request.

  • How do you pass props from one component to another?

  • How to list databases in the settings.py file in Django and can we declare multiple database instances?

  • What is Installed Apps in settings.py?

  • How do you do Two-Factor authentication?

  • psql commands for PostgreSQL

    • List all tables in a database.
    • Connect to a database.

  • Have you used Celery? How does Celery work internally?

  • Is Axios asynchronous?

• Round 1:

  • Projects Done / Tech Stack / K8s

  • Have you worked with Terraform?

  • Tell me a time where you had to learn a new skill.

  • What does your daily responsibilities include, how much coding / team managing?

  • What is your biggest professional achievement so far?

  • Mutable vs immutable difference.

  • When to use a list and when to use a dictionary and when to use tuples?

  • How do you measure the time taken for a function in Python? Imagine you have 100's of functions.

  • Shallow copy vs deepcopy in Python.

  • Hackerrank coding problem - find finest food outlets.

• Round 2:

  • What is the biggest obstacle you have faced?
  • What is your biggest professional achievement so far?
  • Architecture for QAHub.
  • What does your daily responsibilities include, how much coding / team managing?
  • [System Design] Implement a recommendation system for an online bookstore.

• Round 3:

  • [First 30 minutes] - I was grilled on every part of my resume, getting to know more about my roles, responsibilities, and contributions at my current company.
  • [Last 30 minutes] - Hackerrank puzzle problem.

• Round 4:

  • What projects did you do in your current role?
  • Difference between var and let.
  • Difference between Angular and React?
  • Is React MVC?
  • Code in JS to open a URL.
  • Code in JS to refresh the page for every 30 seconds.
  • Given a 4x4 matrix, divide the matrix into 4 equal segments such that each segment is not a square or rectangle and they should not bisect.
    • Answer: It is not possible to divide a 4x4 matrix into 4 equal segments such that each segment is not a square or rectangle, as any partition of a 4x4 matrix into 4 equal parts must result in either 4 squares or 2 rectangles. This is due to the fact that a 4x4 matrix has an equal number of rows and columns, and thus, any partition into 4 equal segments must have either the same number of rows and columns in each segment, resulting in squares, or different numbers of rows and columns in each segment, resulting in rectangles.
  • data = 1010100
  • Sort this data.
  • Write unit tests.
  • Difference between shallow copy and deepcopy.
  • Which module do you use for unit testing?
  • Store username and password in session storage and get them and clear them after 5 minutes.
  • data = "I Like Oracle and Oracle Likes You"
  • Count the frequency of each word in the above string.
  • Since you are a UI developer, do you have any personal blogs to show? I said, "Not completely UI, but based on requirements, I act as a full-stack..."

• Round 5:

  • Your React app is taking time to load, how would you troubleshoot it? What performance techniques do you follow? Let's say you have a webpage, how do you troubleshoot it?

    • Answer: I said I would open the console and check the performance tab to see how much time the static files are taking and I would be using a CDN to get the static files faster.
    • Question: Let's say if storing above 10 MB on a CDN is costly, how would you handle it? I said we can use some kind of compression algorithms to reduce the size that is being transferred over the network.

  • Let's say you have a CRM dashboard where once a user call gets connected, the next step is to fetch metadata like personal info, last 5 transactions, account details, etc... Now, when the customer agent says, "Please wait for a minute, your data is loading," it's a waste of time for the end user. So how would you handle such a scenario?

    • Answer: Asynchronously precompute the data as soon as the user call gets connected and store it in an in-memory cache like Redis.

  • Tell me a situation where you got work that you did not like and yet you had to do it?

  • If there is only frontend work in the team, would you do it?

  • If there is a cool-off period and there is monitoring/support kind of work, will you take it as an opportunity and do it?

  • How do you analyze an SQL query that is taking a lot of time to execute?

  • Design a system where you have to read log files and raise exceptions in it and create a Jira ticket in it.

    • Answer: Edge case: If there are the same exceptions from multiple users, then we should not create multiple tickets. Instead, we only have to raise 1 Jira ticket corresponding to it.

  • Have you used useCallback and useMemo?