This time, we would like to share the real-life experience of one of our programhelp students. He finally passed the Oracle OCI's virtual onsite got the offer, but without our remote assist, he would have failed to answer in several rounds because of the stuck points. The whole process is very typical and suitable for students who are preparing for OCI or other cloud computing interviews.
First round: Hiring Manager interview
First round is HM interview, mainly resume + behavioral questions.
Questions asked by the examiner:
- Follow the resume paragraph by paragraph through the project, such as "What specifically were you responsible for in this project?"
- Standard BQ:Tell me about a challenge you faced,What's your biggest accomplishment.
- Asked about career plans in passing:Why do you want to join OCI.
The experience he had prepared was academic, long but unfocused. The first two BQ's were a bit of a detour, and HM asked for details twice after listening to them, making the atmosphere a bit awkward.
Before the interview, we already helped him to organize the story of STAR framework, and reminded him not to expand too much details, but to talk about Situation + Task first, and then add Action. So he quickly brought the topic back and explained it clearly with a short example. The interviewer nodded obviously, and the atmosphere eased down immediately.
Takeaways from this round: HM The main thing to look at is whether the communication is smooth and the experience is reliable. If the story is too scattered, it will be difficult to move people. We will help participants prepare several "ready to cut" cases in advance during the counseling session, so that they can respond quickly in the real world.
Round 2: OOD (System Design)
The second round is the most crucial technical part. The title is:
Design a Key-Value Database that can run on both primary and replica.
On the surface it seems common, but in reality the interviewer will seize on the details and keep asking questions.
point of follow-up question by the examiner:
- Hot key issues: How to avoid a key becoming a bottleneck if it is accessed frequently?
- Replica synchronization: How do primary and replica align?
- Concurrent control: How do you ensure correctness when multiple writes occur at the same time?
- scalability: How does the architecture scale horizontally if the amount of data grows rapidly?
- error tolerance: How do I failover if primary hangs?
At the beginning, the student only drew a basic structure diagram of primary/replica without mentioning the replication strategy. The examiner immediately asked, "Do you use synchronous or asynchronous? What would be the tradeoff?" When asked about the hot key When he froze, thought for half a day and only said "may have to do sharding", but did not say how to slice. The concurrency issue was even more unimaginable, and the scene was silent for a while.
On the question of "synchronous/asynchronous", we prompted him to add the idea of quorum writing by voice, and he said "we can use more than half of the nodes to confirm to ensure consistency", the interviewer was obviously satisfied. In the hot key area, we reminded him to mention consistent hashing + load balancing, and he immediately added "if a key is overheated, we can do replica expansion and break up the requests through consistent hashing". He was able to follow up when the interviewer pressed him. When the interviewer followed up, he was able to keep up with the question. When we were stuck on concurrency control, we directly prompted for the keyword "optimistic lock", and he immediately said "optimistic lock can be realized by version number or timestamp, and retry in case of conflict".
By relying on these real-time reminders, he defused what would have been an awkward silence and ended up with a solid round.
What I learned in this round: OCI likes to ask about the classic points of distributed storage, and trainees can easily panic on the spot if they are unprepared. We will help him when assisting him Structured answer: first draw the process, and then expand tradeoff point by point, so that the logic is clearer.
Round 3: Coding + System Design Extension
The final round was a combination of coding + resume and design.
coding questions:
Integer to Roman Numerals
The process is:
- Started with a half hour chat about resumes and BQs;
- Then coding, converting integers to Roman numerals;
- After writing the code, the examiner asked him to list the test cases;
- In the end, it comes back to system design, and continues to ask "how to deal with the hot key".
The student actually played well in this interview, but there were still a few obvious stuck points. Firstly, in the coding part, he wrote the code very fast, and the idea was fine, but because he wanted to write out the backbone first, he missed the boundary conditions directly, such as the input is 0, negative numbers or more than 3999 cases are not covered. In the interviewer's eyes, this would appear to be a bit careless. Secondly, in the test case session, he only gave two examples at the beginning, and the interviewer immediately asked "any more", the scene was a bit cold for a while, but after we reminded him with our voice, he added more use cases to cover the boundary and exception cases. Finally, in the system design extension discussion, he almost subconsciously said "sharding", but did not specify how to split, how to route the request, how to deal with data consistency, if this point is not timely to add details, the interviewer will feel that it is just a buzzword and not really understand. If you don't add details on this point, the interviewer will feel that you are just using a buzzword without really understanding it.
What I've learned from this round: OCI coding is not very difficult, but it will definitely look at completeness and extended thinking. It is not enough to only write functions, but to be able to explain test cases and even extend to system level. Through real-time reminders, we upgrade the answers from "able to run" to "able to cover + able to extend".
Oracle VO - FAQ
Q1: Does being fast at writing code always mean extra credit?
A1: Being fast is not a problem in itself, but if you ignore boundary conditions and abnormal inputs, you will make the interviewer feel that you are not rigorous enough. It is recommended that after writing the core logic, you leave 1-2 minutes to check the boundaries of 0, negative numbers, extreme values, and so on.
Q2: Will it be a bad idea to start a test case with only two columns?
A2: This will make the interviewer question your test thinking. It is better to follow the framework of "Normal Inputs + Boundary Cases + Abnormal Inputs" to cover at least 5-6 test cases, so that the interviewer can see that you have thought thoroughly.
Q3: Is it enough to mention "sharding" in system design?
A3: Not enough. What the interviewer wants is your understanding of how sharding works, such as the basis for splitting (by userId, by region), the routing method, how to ensure data consistency, scaling and fault tolerance strategies. It's not enough to just talk about keywords.
Q4: What should I do if I get cold feet during the interview?
A4: You can start by verbalizing what you are thinking about, e.g., "I'm thinking about boundary inputs in addition to the normal case". This is better than silence and lets the interviewer know that you are thinking in an organized way.
Q5: If the boundary is missed while coding, can it be remedied?
A5: Yes. When you find an omission just say, "I just implemented the core logic, now I'd like to add the boundary check." This proactive approach to corrections is often a plus.
Helping you not to get stuck in the interview and get a big company offer
Like this student, many students will encounter similar stuck points in the interview: coding is written too fast and easy to ignore the boundaries, test case is not comprehensive enough to be pursued, system design will only throw key words but lack of details. In fact, these are not the strength is not enough, but the scene is easy to be nervous, resulting in performance greatly reduced.
we programhelp The team has been accompanying the students for a long time to prepare for the interviews in the big factories and provide them:
Remote No Trace Online Aid: Real-time reminding of boundary conditions during the coding process to avoid missing measurements;
speech assistants: test case When being pressed, timely enlightenment of ideas, not cold field;
system design Extension of Ideas: To help you turn "words" into complete answers that "work" on the ground;
Simulated live training: By stepping on potholes and correcting them in advance, you can play steadily in the interview scene.
The end result is that students will no longer be tripped up by small mistakes in interviews, and will be able to show their true level of performance and get a successful offer.
