Meet the Global LINERs
Engineering
Hyowoo Lee / DB Engineering / LINE Plus
Hyowoo started his career as a backend engineer and later became a database consultant. In 2018, he joined LINE to gain experience with the diverse range of databases used by its global services. Even with his impressive background, he saw it was important to understand the autonomous culture of the LINE Database team. We talked to Hyowoo to gain his thoughtful insights about LINE Database.
A quick three-line summary
- Hyowoo is responsible for Redis tasks as a Database Administrator.
- At LINE, he believes that growth comes from collaborating with skilled peers, enhancing his own expertise.
- The key values of the LINE Database team are "technical curiosity," "proactivity," and "positive attitude."
About Work
Q Please introduce LINE's Database team and your responsibilities!
The Database team at LINE manages a wide range of databases used across its services, including RDBMS (MySQL, Oracle, SQL Server, PostgreSQL) and NoSQL (Redis, MongoDB, HBase, Cassandra). We ensure that data meets the specific requirements of each service and develop and operate Cloud-based DBaaS (Database as a Service). I am part of the Redis team, which specializes in managing Redis, a database used extensively in LINE's services. Our team operates one of the largest Redis systems in the industry and builds all sorts of automation and monitoring systems to ensure we manage it efficiently. We are also involved in developing and operating DBaaS for Redis. Currently, I focus on operational tasks, automation projects, troubleshooting, performance analyses and studying open-source code. However, I might take on new responsibilities in the future (laughs). Some team members collaborate directly with the Cloud Service team and participate in all phases of planning and developing our internal private cloud platform, Flava. While we concentrate on managing each DBMS, we also engage in many other projects, contributing to planning and development. *RDBMS: Relational Database Management System (a type of database management system for relational databases) *NoSQL: Not Only SQL, referring to non-relational databases.
Q What aspects of your work do you find enjoyable?
In our Database team, we have the autonomy to explore a wide range of areas beyond our basic responsibilities. I enjoy sharing the insights I’ve gained from all those different tasks through research projects and tech exchanges, which helps to foster team growth rather than just my individual development. This is why I often dedicate time to various research activities! Many colleagues have a strong technical curiosity and actively contribute to various OSS (Open Source Software) projects. I have also analyzed and improved Redis's C code, collaborating with LINE's Developer Relations team to create technical lectures like Database RDBS Tuning, Basic Redis, and Redis Cluster for our members in other countries. Among these lectures, I found the process of creating the Redis Cluster lecture to be the most rewarding and enjoyable. At that time, there were hardly any resources about Redis or Redis Cluster in Korea, so I had to carefully review the code and conduct constant testing to ensure the content was accurate. Looking back, making the effort to share my knowledge significantly contributed to my technical growth. It was fulfilling to contribute to LINE's overall tech exchange and receive positive feedback from the other participants. Additionally, this work led to me being selected as a key player in a “relay campaign” that recognizes colleagues who embody LINE's values, making it a memorable and rewarding experience. I plan to seek similar opportunities in the future to continue growing alongside the company.
Q What is a work-related achievement you consider really memorable?
One of my most memorable achievements was a project that focused on cost reduction (low usage). Many services often experience discrepancies between the expected server specifications during the initial setup and the actual resource usage during operation. For example, there can be underutilized server resources or servers that have been unused for a long time. Given that LINE has numerous services, we believed that the cumulative wasted costs could be significant, so we initiated a team project to address this. We focused on tracking underutilized resources and automating the processes for proper sizing, resource replacement, and returns. This helped us eliminate unnecessary resources and establish a framework to prevent future waste. Thanks to this system, we continue to manage unnecessary costs through regular resource monitoring. As an infrastructure engineer, it was often difficult to quantify my contributions to the company through operations and development. However, seeing tangible figures showing how much we saved in monthly expenses provided an exhilarating sense of achievement.
Challenges and Failures
Q Along the road to those achievements, you must have had some disappointments and failures, too. What was that like?
When managing databases, there are often minor incidents and troubleshooting processes. Database incidents can lead to service disruptions that users experience, making them quite critical. Human error can sometimes be the cause, and I have made mistakes during my work as well. While I don't have any specific incidents that come to mind, I think my small mistakes can be considered failures. However, our team lead has said that if we can resolve incidents well, they can become opportunities for growth rather than just mistakes. Because of this, I’ve had the unusual experience of receiving praise instead of being reprimanded after addressing an incident (laughs). That said, preparing incident reports that cover everything from root cause analysis to preventive measures for the database team can be quite challenging. I strive to turn our recent issues into lessons for technical growth and have made a commitment to prevent them from recurring, aiming to transform these experiences into opportunities for team development.
Q What kind of growth have you experienced through your time at LINE?
It’s a bit embarrassing to say, but I receive comments like "You’ve grown this year" in my peer reviews every year. Beyond my main role in operations, I actively plan and lead various projects, constantly seeking new challenges that create opportunities for growth. While starting both big and small projects can be difficult and overwhelming, collaborating with talented colleagues and receiving their feedback helps me develop new skills along the way. Recently, I revisited C programming for the first time since college. Although I don’t use C often, I needed it to investigate some internal issues with Redis, which is open-source and written in C. I remember studying it diligently. This aligns with the concept of "growing through collaboration," where being part of a talented group makes me feel like I am also improving. I believe LINE is that kind of place for me.
Q What does the word “challenge” mean to you?
In the culture at LINE, I believe that LINE equals challenge. The company places great importance on taking on challenges, setting new goals and tasks that exceed the current capabilities of individuals or teams. Through overcoming the difficulties that arise during this process, we consistently grow from the sense of achievement and experiences gained. On our Database team, many of my colleagues enjoy tackling new and complex problems. When we face challenges, we collaborate, brainstorm, and discuss things together, constantly striving to create better services and solutions.
Thoughts on competencies
Q What abilities and qualities do you believe are necessary for delivering excellent performance in your role?
As a database engineer, there are many important factors such as knowledge, experience, problem-solving skills, ability to collaborate, communication, and reliability. However, I believe that a consistent curiosity about technology and a willingness to take on challenges are the most crucial qualities today. Technology evolves rapidly, and new advancements continually emerge, so having the confidence to stay engaged and adapt is essential for delivering strong performance. That's why our Database team makes a point of hiring new talent. We look for individuals who are unafraid of new challenges in a constantly changing technological and work environment and who have the potential to grow into experts over the long term.
Special experiences at LINE
Q Tell us about the colleagues that you work with at LINE.
Our teams consist of both Japanese and Korean members, and as you move up to the Database organization level, you'll find engineers from even more nationalities. Collaboration and interaction are active not only within teams but also across the entire Database organization, which helps lead to a growing sense of camaraderie over time. I would highlight the atmosphere of professionalism where colleagues support one another, allowing us to focus entirely on our work without concerns about interpersonal issues. In particular, our organization is managed by outstanding leaders at the team, department, and division levels, and many team members are recognized for their expertise in their respective countries. This helps maintain a high level of technical proficiency within the organization. I feel honored to work alongside exceptional individuals who write technical books or regularly contribute to tech blogs. On a personal note, while I may not be widely known (laughs), I serve as a specialist at the Korea Data Agency, overseeing the certification exam for database qualifications and engaging in various advisory activities related to databases. Lastly, I am particularly excited about the growth of our junior colleagues, who consistently deliver excellent performance and embody the spirit of challenge. While it’s difficult for everyone to be a perfect hexagonal talent, I would describe our team as a wonderful orchestra where members with strengths in different areas come together in harmony to create beautiful music through collaboration.
Q Is there a memorable moment from your time at LINE?
One memorable moment that still stands out to me is when my colleagues and I registered for a Brazilian jiu-jitsu class during our lunch break. I still cherish a photo we took on the first day at the dojo; it's a nostalgic memory that I often think about. Unfortunately, due to various reasons like remote work and the dojo's closure during COVID, we eventually drifted apart. However, everyone continued to pursue their own fitness activities, and I have kept jiu-jitsu as my favorite hobby, training at a dojo near my home. I even participate in competitions and have won some medals, enjoying the journey consistently. Had it not been for the joyful memories shared with my colleagues during that time, I might have given up on this challenging sport. I believe my time at LINE has instilled in me the LINER tendency to fully commit to what I start, pushing through to the end without realizing it (laughs).
Q Is there any aspect of LINE’s culture that you think is particularly notable?
LINE has a culture of high autonomy. We set and review our plans quarterly and biannually, and during this process, each person must identify their own tasks. Individuals decide what work they want to pursue and share their goals. While the organization collects this information to prioritize tasks, there is a strong respect for personal autonomy. For those who have diverse interests, this means they can receive significant support from the organization in pursuing areas they are passionate about, which I think is a great aspect of our culture.
Wrap-up
Q Do you have any goals you personally want to achieve at LINE?
As I recently set my work goals for this year, I can answer this relatively easily. Just as there is no eternal technology for engineers, I want to embrace new technologies and develop my expertise. So far, I have worked with Oracle, PostgreSQL, and MySQL, and I am currently focused on Redis. I wish to explore even more databases in the future. If a new open-source database emerges that is as attractive as Redis, I would love to research it and implement it at LINE quickly. I also have a grand goal of contributing to open-source code to make a positive impact on the world (laughs). My primary goal is to be recognized as "Hyowoo, the database expert," but I also aim to keep on growing so that LINE is firmly known as the best in database expertise.
Q Any message for those interested in this position?
LINE offers a wide array of services, making it a comprehensive platform in the infrastructure domain, from small social services to large financial systems. Here, you can experience not just database operations but also automation development, monitoring system setup, open-source research, introducing new features, communication with various service owners, and the development and support of DBaaS. We are currently hiring for several positions and are looking for candidates who embody key qualities such as technical curiosity, being proactive, and having a positive attitude. Ideally, we seek individuals who can work together over the long term. A commitment to finding root causes, actively researching and experimenting with new technologies or tools—if you have curiosity about databases and a desire for growth, we encourage you to apply! Our Database team members come from all sorts of backgrounds. We have experts in specific DBMS, those proficient in various DBMS, specialists in data modeling and query tuning, skilled coders, and system engineering experts—all of whom are proactive and challenge-driven. We even have a super new hire who has achieved remarkable growth and won the SIG (Service Infrastructure Group) Professionals Award! While everyone has different backgrounds and specialties, we share our expertise, positively influence each other, and maintain teamwork through collaboration. If you're interested in joining a global and expansive database environment where we can grow together, please check out the job postings below! ※ [LINE PLUS] Redis DevOps Engineer : https://careers.linecorp.com/ko/jobs/2687 ※ [LINE PLUS] MongoDB Engineer : https://careers.linecorp.com/ko/jobs/2624
