1. Basic Information
Company: ZhongzhiField: Backend Development with 0-5 Years ExperiencePosition: C++ Development EngineerInterview Date: 2021-10-15Interview Format: PhoneInterview Duration: 90 minutesIs Recording Available: YesRecording Notes: Review is not anonymized, please maintain confidentiality
Recording and Transcription File: https://articles.zsxq.com/id_5frz7dzp4n1j.html
Interview Background: Conducted at Guomei in Beijing
2. Interview Review
2.1 Interview Questions
1Please introduce yourself. (Implicit in the interview opening)2Please describe the distributed architecture upgrade project you were responsible for at Yaxin Technology, especially how you addressed the shortcomings of a single-machine system?3In the optimization of in-memory databases (MDB), how did you resolve consistency and performance issues in a distributed environment?4In the audio and video service system, why did you choose coroutines instead of multithreading? What were the optimization effects?5Please compare the differences between const and #define and their applicable scenarios.6Please analyze the precedence of <span>*p++</span> and <span>++*p</span> in the code and predict the output result.7Why did you leave Guomei?8What is your career plan?
2.2 Interview Review and Evaluation Report
Part One: List of Interviewer Questions
The following are the questions posed by the interviewer extracted from the interview record, focusing on technical details, project experience, foundational knowledge, and career motivation:
1Please introduce yourself.2Please describe the distributed architecture upgrade project you were responsible for at Yaxin Technology, especially how you addressed the shortcomings of a single-machine system?3In the optimization of in-memory databases (MDB), how did you resolve consistency and performance issues in a distributed environment?4In the audio and video service system, why did you choose coroutines instead of multithreading? What were the optimization effects?5Please compare the differences between const and #define and their applicable scenarios.6Please analyze the precedence of <span>*p++</span> and <span>++*p</span> in the code and predict the output result.7Why did you leave Guomei?8What is your career plan?
Part Two: Detailed Process and Comments on Candidate’s Answers
1
Please introduce yourself
•Response Process: The candidate briefly introduced their work experience, divided into two stages: Yaxin Technology (5 years) and Guomei (3 years). At Yaxin Technology, they were responsible for the distributed architecture upgrade of the telecom billing system, including refactoring the self-maintaining engine module, optimizing billing time using remote call frameworks and queues, developing a fully in-memory database, and implementing sharding through a proxy layer. At Guomei, they were responsible for the reliable communication system in the audio and video department, optimizing scheduling with coroutines, using Redis for state consistency, and maintaining the Reduce component.•Comments: The response was well-structured, highlighting key project experiences and technical highlights, demonstrating the candidate’s architecture design and optimization capabilities. However, it lacked quantifiable descriptions of personal technical stack and achievements (e.g., specific performance improvement percentages). It is recommended to emphasize personal contributions more specifically in the self-introduction.2
Please describe the distributed architecture upgrade project you were responsible for at Yaxin Technology, especially how you addressed the shortcomings of a single-machine system?
•Response Process: The candidate analyzed the shortcomings of the single-machine system (thread crashes leading to process exits, high module coupling, long billing cycles) and detailed the optimization plan: splitting the business into independent nodes, defining interfaces using SDL language, implementing disaster recovery through message queues and monitoring frameworks, and addressing data duplication and performance loss issues (e.g., MD5 deduplication, transport layer optimization).•Comments: The candidate was able to systematically analyze the problem and propose solutions, showcasing experience in distributed system design. However, the response did not mention specific technology choices (e.g., the RPC framework or queue types used), lacking supporting details. It is recommended to supplement with actual cases and data to enhance persuasiveness.3
In the optimization of in-memory databases (MDB), how did you resolve consistency and performance issues in a distributed environment?
•Response Process: The candidate mentioned achieving sharding and load balancing through a proxy layer and performed performance optimizations (e.g., splitting long transactions, preloading shared memory, preallocating memory). In terms of consistency, they ensured strong consistency through reduced lock granularity and incremental updates.•Comments: The response covered the core challenges of distributed databases, reflecting an understanding of the balance between consistency and performance. However, it did not mention specific consistency protocols (e.g., Paxos or Raft) or persistence mechanisms, which may expose a lack of depth in underlying knowledge. It is recommended to discuss distributed algorithm practices in more depth.4
In the audio and video service system, why did you choose coroutines instead of multithreading? What were the optimization effects?
•Response Process: The candidate explained that coroutines are more lightweight, reducing thread-switching overhead, suitable for I/O-intensive tasks (e.g., blocking network requests), and adaptable to low-configuration server environments (4 cores/8GB memory). High concurrency is achieved through cooperative scheduling.•Comments: The response correctly pointed out the advantages of coroutines, demonstrating an understanding of concurrency models. However, it did not compare other solutions (e.g., asynchronous I/O) or mention specific coroutine libraries (e.g., libco), lacking technical depth. It is recommended to strengthen the response with performance metrics (e.g., throughput improvement).5
Please compare the differences between const and #define and their applicable scenarios
•Response Process: The candidate stated that const is used to ensure data immutability (e.g., parameter protection), while #define is suitable for high-frequency calling scenarios to avoid function call overhead (e.g., inline optimization).•Comments: The response is generally correct but too brief. It did not mention key points such as type safety, scope differences, or compile-time processing, appearing superficial. It is recommended to explain the potential risks of macros (e.g., debugging difficulties) and the compiler optimization effects of const in more depth.6
Please analyze the precedence of <span>*p++</span> and <span>++*p</span> in the code and predict the output result
•Response Process: The candidate speculated that the output would be “10” and “20”, but was not entirely sure about the precedence rules and expressed uncertainty about type conversion and reference behavior, believing that specific environment verification is needed.•Comments: The candidate showed unfamiliarity with precedence rules, reflecting a weakness in foundational knowledge of C/C++. In actual interviews, such questions test language proficiency, and the candidate’s hesitation may affect technical credibility. It is recommended to strengthen practice on language features and operator precedence.7
Why did you leave Guomei?
•Response Process: The candidate mentioned a contraction in business direction (the company’s strategic shift towards core e-commerce business leading to resource cuts) and a drive for technical interest (hoping to shift towards underlying technologies such as storage, scheduling optimization, and algorithms).•Comments: The response is reasonable, avoiding negative evaluations and reflecting proactivity in career development. However, it did not sufficiently explain how to combine past experiences with new directions; it is recommended to more specifically relate personal skills to future goals.8
What is your career plan?
•Response Process: The candidate emphasized a desire to shift towards underlying technologies (e.g., storage, scheduling optimization) and algorithms, mentioning self-learning methods (reading code, business problem-driven, multi-channel learning).•Comments: The response demonstrated learning ability and technical enthusiasm, but the plan was somewhat vague, lacking mention of short-term and long-term goals. It is recommended to clarify timelines and specific skill enhancement plans to demonstrate the feasibility of the plan.
Part Three: Summary Evaluation and Improvement Suggestions
Evaluation Result: Not Passed Based on the candidate’s responses, the overall performance did not meet the expectations for a senior technical position. The candidate has rich practical experience in project experience, but there are significant deficiencies in technical depth and foundational knowledge, especially in C/C++ language features and the underlying principles of distributed systems. Additionally, the responses lacked specific data and supporting details, affecting credibility.
Improvement Suggestions:
1Strengthen foundational knowledge learning: Focus on reviewing C/C++ language features, such as operator precedence, memory management, type systems, etc., and consolidate through coding practice.2Deepen knowledge of distributed systems: Learn consistency protocols (e.g., Raft), distributed transaction processing, and illustrate with actual cases in projects.3Enhance response structure and details: When describing projects, adopt the STAR (Situation, Task, Action, Result) method, quantify results (e.g., performance improvement percentages), and clarify reasons for technology choices.4Clarify career planning: Set short-term (1-2 years) and long-term (3-5 years) goals, combining existing experience with future directions to demonstrate a coherent career path.5Enhance technical breadth and depth: Focus on mainstream technologies in the industry (e.g., cloud-native, microservices) and improve practical abilities through open-source projects or certifications.
The candidate needs to more confidently and accurately demonstrate technical abilities in subsequent interviews, avoiding uncertain expressions.It is recommended to participate in mock interviews and technical training to bridge the gap.
Don’t overthink it—just go for the interviewRecommended Reading: Classic Materials on Distributed System Architecture