Haozhe Zhang

I will join the College of Computing and Data Science (CCDS) at Nanyang Technological University (NTU) as a Nanyang Assistant Professor in November 2026.

I am currently a postdoctoral researcher in the Data Systems and Theory (DaST) Group at the University of Zurich. I received my DPhil in Computer Science from the University of Oxford, advised by Prof. Dan Olteanu.

I am a database systems researcher with a strong appreciation for theory. I design algorithms with provable guarantees and work to preserve those guarantees in practical query optimizers and engines. In particular, I focus on two problems: cardinality estimation, estimating query result sizes reliably; and incremental view maintenance, keeping query results up to date as data changes.

Funded positions for PhD students, research interns, and postdoctoral researchers will be available in my group at NTU in 2027. More information →

News

[Jul 2026]I will join NTU CCDS as a Nanyang Assistant Professor in November 2026.
[May 2026]Received the SIGMOD 2026 Distinguished Reviewer Award.
[Jan 2026]LpBound passed reproducibility: artifacts available, evaluated and reusable, and results reproduced.
[Jan 2026]Gave a research talk on cardinality estimation with guaranteed upper bounds at TUMuchData, Technical University of Munich.
[Dec 2025]Our work on correlation-aware cardinality estimation was accepted to SIGMOD 2026.

Earlier news

[Dec 2025]Gave a research talk at the Wangxuan Institute, Peking University.
[Oct 2025]Our ICDT 2025 paper was invited to the ACM TODS special issue.
[Sep 2025]Gave a research talk at the Department of Computer Science, Tsinghua University.
[Jun 2025]Received the Best Paper Award at SIGMOD 2025.

Selected Publications

* indicates alphabetical author order, as customary in theoretical computer science venues.

CorrBound: Cardinality Estimation Accounting for Inter- and Intra-relation Correlations. [paper]

Christoph Mayer, Haozhe Zhang, Mahmoud Abo Khamis, Kyle Deeds, Dan Olteanu, Dan Suciu

SIGMOD 2026.

Conjunctive Queries with Free Access Patterns Under Updates. [paper, arxiv]

* Ahmet Kara, Milos Nikolic, Dan Olteanu, Haozhe Zhang

LMCS Journal 2025. Invited journal version of ICDT 2023 paper

LpBound: Pessimistic Cardinality Estimation Using Lp-Norms of Degree Sequences. [arxiv, code, video, website, results reproduced]

Haozhe Zhang, Christoph Mayer, Mahmoud Abo Khamis, Dan Olteanu, Dan Suciu

SIGMOD 2025. Best Paper Award

Tractable Conjunctive Queries over Static and Dynamic Relations. [paper, slides]

* Ahmet Kara, Zheng Luo, Milos Nikolic, Dan Olteanu, Haozhe Zhang

ICDT 2025. Invited to TODS

View all publications →

Selected Awards

ACM SIGMOD Distinguished Reviewer Award, 2026
ACM SIGMOD Best Paper Award, 2025
ICDT Best Paper Award, 2019

Teaching

Lecturer: Foundations of Data Science, University of Zurich, Fall 2024
Teaching Assistant:
- Foundations of Data Science, Efficient Algorithms, and Modern Data Analytics, University of Zurich
- Database System Implementation, University of Oxford

Service

Program Committee:
- ACM SIGMOD (2025, 2026)
- IEEE ICDE (2026)
Reviewer:
- The VLDB Journal (2025)
- ACM Transactions on Database Systems (2023, 2024)
- Logical Methods in Computer Science (2022, 2024)