Hangdong Zhao

I am an FTE at Microsoft Gray Systems Lab. I work on providing guarantees for data systems.

I received my B.S. in Math in 2020 from the tropical National University of Singapore. I was advised by Jonathan Scarlett on neural architectural search.

After years of fun work advised by Paris Koutris, I received my Ph.D. in 2025 from the wintry University of Wisconsin-Madison.

July 2026: FlowLog (and its demo) has been accepted to VLDB and SPLASH 2026. It is the fastest Datalog engine that I am aware of.
March 2026: I gave talks at Wisconsin and CMU Database Group on my recent use of AI agents for industrial-grade query optimization.
November 2025: I gave a talk at NWDS on our recent research efforts on "Modernizing the Yannakakis Algorithm".

2027

Optimal Convergence of Iterative Methods for Datalogo
Simon Frisk, Hangdong Zhao, Hung Ngo, Kirk Pruhs, Benjamin Moseley, Sungjin Im, Paraschos Koutris
PODS'27

2026

Rubberband: Memory-Elastic, Skew-Tolerant GPU Hash Joins slides
Hangdong Zhao, Rathijit Sen, Craig Peeper, Matteo Interlandi
VLDB'26 ADMS
FlowLog: Efficient and Extensible Datalog via Incrementality slides flowlog-rs.com github SPLASH'26 demo
Hangdong Zhao, Zhenghong Yu, Srinag Rao, Simon Frisk, Zhiwei Fan, Paraschos Koutris
VLDB'26
How Out-of-Bounds Are Your Cardinality Estimates? demo
Mihail Stoian, Tiemo Bang, Hangdong Zhao, Jesús Camacho-Rodríguez, Yuanyuan Tian, Andreas Kipf
VLDB'26 Demo
One Join Order Does Not Fit All: Reducing Intermediate Results with Per-Split Query Plans
Yujun He, Hangdong Zhao, Simon Frisk, Yifei Yang, Kevin Kristensen, Paraschos Koutris, Xiangyao Yu
VLDB'26
Demo of SemWeave: Semantic Common Expressions for LLM-powered Query Processing
Md. Tareq Mahmood, Venkatesh Emani, Hangdong Zhao, Shivaram Venkataraman
SIGMOD'26 Demo
I Can't Believe It's Not Yannakakis: Pragmatic Bitmap Filters in Microsoft SQL Server slides
Hangdong Zhao, Yuanyuan Tian, Rana Alotaibi, Bailu Ding, Nicolas Bruno, Jesús Camacho-Rodríguez, Vassilis Papadimos, Ernesto Cervantes Juárez, Cesar Galindo-Legaria, Carlo Curino
CIDR'26

2025

2024

Evaluating Datalog over Semirings: A Grounding-based Approach Datalog 2.0'24
Hangdong Zhao, Shaleen Deep, Paraschos Koutris, Sudeepa Roy, Val Tannen
PODS'24
*Tight Bounds of Circuits for Sum-Product Queries slides
Austen Fan, Paraschos Koutris, Hangdong Zhao
PODS'24
Distinguished Paper Award (invited to J. ACM)
Predicate Transfer: Efficient Pre-Filtering on Multi-Join Queries
Yifei Yang, Hangdong Zhao, Xiangyao Yu, Paraschos Koutris
CIDR'24
Conjunctive Queries with Negation and Aggregation: A Linear Time Characterization slides demo TODS'25
Hangdong Zhao, Austen Fan, Xiating Ouyang, Paraschos Koutris
PODS'24
Distinguished Paper Award (invited to TODS)

2023

2021