Time：2:00-2:45 PM , July 18th 2023

Location：106,WICT

Abstract:： 
To support analytics on massive graphs such as online social networks, RDF, Semantic Web, etc. many new graph algorithms are designed to query graphs for a specific problem, and many distributed graph processing systems are developed to support graph querying by programming. In this talk, first, we focus on RDBM, which has been well studied over decades to manage large datasets. We revisit the issue how RDBMS can support graph processing by SQL. Our work is motivated by the fact that there are many relations stored in RDBMS that are closely related to a graph in real applications and need to be used together to query the graph, and RDBMS is a system that can query and manage data while data may be updated over time. To support graph processing, we propose new relational algebra operations that can be defined by the basic relational algebra operations with group-by-&-aggregation. We revisit SQL recursive queries and show that the new operations with others are ensured to have a fixpoint, and enhance the recursive WITH clause in SQL'99. Such enhanced recursive WITH Clause can be supported by major RDBMSs. Second, we discuss how to translate such newly introduced operations into a distributed graph processing system and how to optimize queries by separating communication from computation, in order to achieve high efficiency.

Bio：
Dr Jeffrey Xu Yu is a Professor in the Department of Systems Engineering and Engineering Management, The Chinese University of Hong Kong. His current main research interests include graph algorithms, graph processing systems, and query processing in database systems. Dr. Yu served as an Information Director and a member in ACM SIGMOD executive committee (2007-2011), an associate editor of IEEE TKDE (2004-2008), and an associate editor in VLDB Journal (2007-2013). Currently he servers as an associate editor of ACM TODS, WWW Journal, etc. Dr. Yu served/serves in many organization committees and program committees in international conferences/workshops including PC Co-chair of APWeb'04, WAIM'06, APWeb/WAIM'07, WISE'09, PAKDD'10, DASFAA'11, ICDM'12, NDBC'13, ADMA'14, CIKM'15, Bigcomp17, DSAA'19, CIKM'19, and DASFAA'20, and conference general Co-chair of APWeb'13, ICDM'18, and ADC'22.