Software Engineer 3, Query Optimization

MongoDB; Dublin (CA); Hybrid; USD 100,000 - 145,000; Full time

Job summary

MongoDB Inc. is seeking a Software Engineer for the Server Query team in Dublin to help build a distributed open-source query engine and optimize query performance.

You will work on parsing, optimization, plan selection, and execution, collaborating with drivers, cloud services, and enterprise tools in a hybrid setup.

The role is ideal for hands-on contributors with a CS foundation and a passion for scalable data systems.

Qualifications

• 3+ years of experience in data-intensive environments.
• Hands-on experience building industrial-strength software.
• Strong fundamentals in data structures, algorithms, and software design/architecture.

Responsibilities

• Understand and improve current functionality of the MongoDB query engine.
• Identify, design, implement, test, and support new features related to query performance and robustness, diagnostics, and language enhancements.
• Work with other engineers to coordinate changes in a large, feature-rich code base and collaborate with client drivers, cloud services, and enterprise tools.

Skills

Data structures

Algorithms

Software design

Codebase familiarity

Education

B.Sc in Computer Science

Job description

Join the MongoDB Server Query team, and help us build a world-class distributed open source query engine. Our team plays a crucial role in the experience and performance of data processing. We are responsible for the MongoDB Query Language and the lifecycle of each query, from parsing to optimization to plan selection and finally execution. This also includes our geospatial search and update subsystems.

Our global team is growing fast. In North America, we have a presence across the US and Canada including New York, West Coast, Toronto. In Europe, we have a presence in Dublin, Germany, France, Netherlands, UK, Bulgaria, Spain and Italy currently. We support office-based and remote work and align projects with convenient work hours.

We have tons of interesting problems to solve with direct impact on users for transactional, time-series and analytical workloads. We need your help to design and build the heart of a distributed, flexible schema, document database.

We are looking to speak to candidates who are based in Dublin for our hybrid working model.

Candidate Profile

• 3+ years of experience in data intensive environments
• Hands‑on experience building industrial‑strength software
• Solid computer science fundamentals, with strong competencies in data structures, algorithms, and software design/architecture
• Experience with large code bases
• B.Sc in Computer Science or similar field, or equivalent practical experience
• Experience in developing database systems is a plus
• Interest in the theory and practice of database query engines. Hands‑on experience or M.Sc./Ph.D in the domain is a plus

Position Expectations

• Understand and improve current functionality of the MongoDB query engine
• Identify, design, implement, test, and support new features related to query performance and robustness, query language enhancements, diagnostics for query performance problems, and integration with other products and tools
• Work with other engineers to coordinate seamless changes in a feature‑rich, large code base
• Work with other teams including client drivers, cloud services, enterprise tools, support, consulting, education, and marketing to coordinate changes or contribute to their projects

Success Measures

• In three months you’ll have contributed to the development of a project slated for the next major version, as well as fixed a few bugs in a minor version of our latest stable release series
• In six months, you’ll have taken on code review responsibilities and are involved in reviewing the design for new features
• In twelve months, you’re making significant contributions to the development of a new major features

About MongoDB

MongoDB is built for change, empowering our customers and our people to innovate at the speed of the market. We have redefined the data platform for the AI era, enabling builders to create, transform, and disrupt industries with software. MongoDB’s unified data platform, the most widely available, globally distributed data platform on the market, helps organizations modernize legacy workloads, embrace innovation, and unleash AI. Our cloud-native platform, MongoDB Atlas, is the only globally distributed, multi‑cloud data platform and is available across AWS, Google Cloud, and Microsoft Azure.

With offices worldwide and over 67,000 customers, including AI-native startups and approximately 75% of the Fortune 100, relying on MongoDB for their most important applications, we’re powering the next era of software.

Our compass at MongoDB is our Leadership Commitment, guiding how and why we make decisions, show up for each other, and win. It’s what makes us MongoDB.

To drive the personal growth and business impact of our employees, we’re committed to developing a supportive and enriching culture for everyone. From employee affinity groups, to fertility assistance and a generous parental leave policy, we value our employees’ wellbeing and want to support them along every step of their professional and personal journeys. Learn more about what it’s like to work at MongoDB, and help us make an impact on the world!

MongoDB is committed to providing any necessary accommodations for individuals with disabilities within our application and interview process. To request an accommodation due to a disability, please inform your recruiter.

MongoDB is an equal opportunities employer.