Haozhe Zhang

I am a postdoctoral researcher at the DaST Group at the University of Zurich. Before that, I was a DPhil student at University of Oxford, supervised by Prof. Dan Olteanu.

I am interested in both theoretical and practical aspects of database systems, with a focus on incremental view maintenance, cardinality estimation, and database theory.

News

[Jan 2026]LpBound passed reproducibility: artifacts available, artifacts evaluated and reusable, results reproduced.
[Jan 2026]Research talk: Cardinality Estimation with Guaranteed Upper Bounds, TUMuchData, Technical University of Munich.
[Dec 2025]Research talk: Designing Data Systems with Provable Performance Guarantees, Wangxuan Institute, Peking University.
[Dec 2025]Accepted to SIGMOD 2026, inter- and intra-relation correlation-aware cardinality estimation.
[Oct 2025]ICDT 2025 paper invited to ACM TODS special issue.
[Sep 2025]Research talk: Bridging Theory and Practice—Building High-Performance Data Systems, Department of Computer Science, Tsinghua University.
[Jun 2025]Best Paper Award at SIGMOD 2025.

Publications

(* indicates alphabetical author ordering, as is standard in theoretical CS venues)

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

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

SIGMOD 2026 (to appear).

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]

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

SIGMOD 2025. Best Paper Award

LpBound in Action: Cardinality Estimation with One-Sided Guarantees. [paper, video]

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

SIGMOD 2025. Demo Paper

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

F-IVM: Analytics over Relational Databases under Updates. [arxiv]

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

VLDB Journal 2024. Special issue on Machine Learning and Databases

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

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

ICDT 2023. Invited to LMCS Journal

Trade-offs in Static and Dynamic Evaluation of Hierarchical Queries. [paper, arxiv]

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

LMCS Journal 2023.

Evaluation Trade-Offs for Acyclic Conjunctive Queries. [paper]

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

CSL 2023.

Machine learning over static and dynamic relational data. [paper, arxiv]

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

DEBS 2021.

F-IVM: Learning over Fast Evolving Relational Data. [paper, arxiv]

Milos Nikolic, Haozhe Zhang, Ahmet Kara, Dan Olteanu

SIGMOD 2020. Demo Paper

Trade-offs in Static and Dynamic Evaluation of Hierarchical Queries. [paper, arxiv, slides]

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

PODS 2020.

Maintaining Triangle Queries under Updates. [paper, arxiv]

* Ahmet Kara, Hung Q. Ngo, Milos Nikolic, Dan Olteanu, Haozhe Zhang

TODS Journal 2020. Special issue of best papers at ICDT 2019

Counting Triangles under Updates in Worst-Case Optimal Time. [paper, arxiv, slides]

* Ahmet Kara, Hung Q. Ngo, Milos Nikolic, Dan Olteanu, Haozhe Zhang

ICDT 2019. Best paper award

Counting Triangles under Updates. [paper]

* Ahmet Kara, Hung Q. Ngo, Milos Nikolic, Dan Olteanu, Haozhe Zhang

AMW 2018. Workshop Paper

A State Machine System for Insider Threat Detection. [paper]

Haozhe Zhang, Ioannis Agrafiotis, Arnau Erola, Sadie Creese, Michael Goldsmith

GraMSec 2018. Workshop Paper

Service

PC Member: ICDE (2026), SIGMOD (2025, 2026)

Reviewer: VLDB Journal (2025), TODS (2023, 2024), LMCS (2022, 2024)

Teaching

Lecturer

Foundations of Data Sciences (UZH, Fall 2024)

Teaching Assistant

Foundations of Data Sciences (UZH, Fall 2020 - Fall 2023, Fall 2025)
Efficient Algorithms (UZH, Spring 2021 - Spring 2025)
Modern Data Analytics (UZH, Fall 2023, 2025)
Database System Implementation (Oxford, Hilary 2019)

Supervision

PhD: Christoph Mayer (co-supervised, 2024–present)
MSc theses: 5 students (2023–2025)