Date Posted
20 Nov 2021

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PhD Project
Cornell University

PhD Position in Query Optimization

20 Nov 2021

NOTE: this position listing has expired and may no longer be relevant!

Position Description

The database group at Cornell University is looking for an outstanding PhD student to conduct research in the area of “query optimization”. Cornell University, one of the eight Ivy League universities, is consistently ranked as one of the best universities worldwide. The project will be supervised by Prof. Immanuel Trummer with a starting date between June and September 2018.

Topic. The goal of query optimization is to translate a declarative query, describing data to generate, into an optimal query plan, describing how to generate it. A good query optimizer can easily make the difference between seconds (for an optimal plan) and hours (for a sub-optimal plan) of execution time.

For that reason, query optimization has received significant attention in the database research community as well as in industry. Among the unsolved challenges in query optimization are for instance the following:
– Scale: traditional query optimizers generate optimal plans only for queries up to a certain size, before switching to cheap heuristics. We need more efficient optimization methods to push the limits in terms of query sizes we can optimize.
– Expressiveness: traditional query optimizers use simplistic problem models that cannot model certain aspects of modern data processing platforms. We need to make optimizer problem models more expressive and design corresponding algorithms.
– Robustness: traditional query optimizers rely on a cost model estimating execution cost for a given plan. All too often, those cost models produce erroneous estimates which may lead to the selection of highly sub-optimal plans. We need more reliable cost models or query optimization approaches that do not rely on simplifying cost models altogether.

The Cornell database group is currently working on projects that address each of those challenges.

Tasks. Your tasks as PhD student will include
– to conduct research on query optimization and related topics,
– to disseminate the results of your research via publications at top-tier conferences and journals in the database area, and
– to assist in teaching courses in the computer science department.

Profile. The ideal candidate has
– excellent grades and recommendations, ideally first experiences as a researcher,
– strong analytical skills and significant coding experience, and
– strong background in databases, optimization, and ideally in query optimization.

How to Apply

As a first step, interested students should send a CV to Prof. Immanuel Trummer (e-mail: In addition, they must apply to the Cornell Computer Science PhD Program as described under The deadline for this application is the ***15th of December***, no extensions can be granted.

Position Category: Technology. Position Type: PhD Project.