Publish date: Jan 10, 2024 12:01:13 PM

Introduction

LeetCode, the go-to platform for coding interview preparation, has seen explosive growth in recent years. With millions of users honing their skills on its vast library of problems, LeetCode faced a critical challenge: how to handle the massive influx of data and deliver a seamless, high-performance experience.

Founding and Mission:

Established in 2015 in the heart of Silicon Valley, LeetCode boasts a diverse team from all around the globe.
Their mission is simple yet powerful: level up coding skills and accelerate career growth. They do this by providing:
- A vast library of coding problems categorized by difficulty and topic.
- Interactive coding environment to practice and test solutions.
- Discussion forums for peer-to-peer learning and problem-solving.
- Personalized learning paths and progress tracking tools.

Impact and Reach:

LeetCode has become a go-to resource for:
- Job seekers: Tech giants like Facebook, Google, and Hulu use LeetCode problems in their interviews. Mastering LeetCode problems significantly boosts interview confidence and the probability of landing dream jobs.
- Coding enthusiasts: LeetCode provides a fun and challenging way to improve problem-solving skills, learn new algorithms and data structures, and stay sharp.
- Students: LeetCode bridges the gap between theoretical knowledge and practical application, preparing students for real-world coding challenges.
With millions of users from diverse backgrounds and skill levels, LeetCode fosters a vibrant and supportive coding community.

Beyond the Platform:

LeetCode actively engages with its community through:
- LeetCode Explore: A curated learning path for beginners, guiding them through essential coding concepts.
- LeetCode Contests: Regular coding competitions to test skills, win prizes, and earn recognition.
- LeetCode Learning: Educational resources like articles, tutorials, and video courses to deepen coding knowledge.

The Challenge: Data Overload

LeetCode's current data warehouse, built on an OLTP database, was struggling under the weight of terabytes of user activity data. Using this OLTP database, queries took ages, impacting user experience and hindering LeetCode's ability to analyze trends and optimize the platform. Scaling up the existing system proved costly and unsustainable.

They also had other considerations:

Want sub-second to single digital query response across TBs of data
Want an OLAP database that was easy to setup and operate
Want user facing analytics
Want to make more data driven decisions

The Solution: StarRocks to the Rescue

LeetCode turned to StarRocks, a new-generation distributed MPP database built for real-time analytics. StarRocks promised blazing-fast query performance, horizontal scalability, and cost-efficiency – exactly what LeetCode needed.

Other benefits of using StarRocks were:

Performant multi-table joins, reduce over-engineering on data modeling
Using external catalog to query data from MySQL to do quick analytics prototyping
Easy setup using k8s operator

Migrating to StarRocks: A Smooth Transition

The migration process was surprisingly smooth. LeetCode's engineers leveraged StarRocks' compatibility with existing data formats and SQL dialects, ensuring minimal disruption to their workflow. StarRocks' team was very supportive and robust documentation further eased the transition.

The Results: A Quantum Leap in Performance

LeetCode's data platform experienced a dramatic transformation with StarRocks:

Queries 100x Faster: Complex analytics that previously took hours now finished in seconds, empowering LeetCode to gain real-time insights into user behavior and platform performance. Additionally, some queries that couldn't run in the OLTP system were able to run successfully in StarRocks.
Unlimited Scalability: StarRocks' horizontal scaling effortlessly accommodated LeetCode's growing data volume, eliminating concerns about future bottlenecks.
Cost Savings of 80%: Compared to the a similar managed OLAP solution on GCP, StarRocks delivered significant cost savings, allowing LeetCode to reinvest in platform development and user experience.

The use of StarRocks allowed the company to

Being more data driven -- no guessing / intuition game -- more confidence
Uncovered important insights, empowering us to deliver enhanced content and product experiences for our users

Beyond Performance: A Strategic Partnership

LeetCode's success with StarRocks goes beyond just performance gains. The two companies have established a strong partnership, collaborating on optimizing LeetCode's data infrastructure and developing innovative features leveraging StarRocks' capabilities.

A Scalable Future for Coding Prep

With StarRocks as its data engine, LeetCode is poised for continued growth. The platform can now handle even larger user bases and data volumes, ensuring a smooth and rewarding experience for aspiring coders worldwide. LeetCode's story serves as a testament to the power of StarRocks in empowering businesses to unlock the potential of their data and achieve their strategic goals.