1. Key Laboratory of Data Engineering and Knowledge Engineering (MOE), and School of Information, Renmin University of China, Beijing, China
2. Computer Science Department, Rutgers University, New Brunswick, NJ, USA
3. Department of Computer Science and Technology, Tsinghua University, Beijing, China
4. IIIS, Tsinghua University, Beijing, China
5. High School Affiliated, Renmin University of China, Beijing, China
6. Database R&D Department, Tencent, Shenzhen, China