Skip to content

Zijie Zhao

Portrait of Zijie Zhao

PhD student in Computer and Information Science at UPenn (opens in a new window), advised by Ryan Marcus (opens in a new window) in the Penn Database Group (opens in a new window).

I build adaptive software systems that learn from execution and improve how they behave, with a current focus on database engines.

Codex usage

Updated

18B lifetime tokens · 257 active days in the past year

Research

  1. 01

    Adaptive execution

    How can a database choose better physical behavior at microsecond timescales?

    Key paper: Piece of CAKE

  2. 02

    Workload understanding

    What do production traces hide about the work users actually wanted to run?

    Key paper: Survivorship Bias

  3. 03

    Self-evolvable software

    Can software adapt inputs, policies, and implementations instead of waiting for retraining or manual tuning?

    Key paper: CodeImprove

Publications

  • A microsecond-scale learning system selects a physical kernel for each data morsel, reducing end-to-end workload latency by up to 2×.

  • Shows how production traces encode a negotiation between users and platforms—and why the queries missing from those traces matter.

    * All authors contributed equally.

  • Adapts out-of-scope programs with semantics-preserving transformations, improving deep code models without frequent retraining.

  • An ontology-aware vision–language foundation model for zero-shot nuclei classification across tissues and unseen cell classes.

Updates

Education

  • 2024–Now

    PhD, Computer and Information Science

    University of Pennsylvania

  • 2026

    MA, Statistics and Data Science

    The Wharton School, University of Pennsylvania

  • 2024

    BE, Computer Science

    Tianjin University

Connect