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Yannis Ioannidis' keynote speech at SEBD 2023, Padua (Italy)

On the 3rd of July 2023, Yannis Ioannidis delivered a keynote talk at the 31st Symposium on Advanced Database Systems(SEBD) in Galzignano Terme (Padua, Italy).

Title: "User-Defined Functions in Relational Databases: Challenges and Promising Solutions based on YeSQL"

The diversity and complexity of modern data management applications have led to the extension of the relational paradigm with syntactic and semantic support for User-Defined Functions (UDFs). Although well-established in traditional DBMS settings, UDFs have become central in many application contexts as well, such as data science, data analytics, and edge computing. Still, a critical limitation of UDFs is the impedance mismatch between their evaluation and relational processing.

In this talk, I will first give an overview of the area and the technical challenges that UDF processing brings. I will then present YeSQL, an SQL extension with rich UDF support along with a pluggable architecture to easily integrate it with either server-based or embedded database engines. YeSQL currently supports Python UDFs fully integrated with relational queries as scalar, aggregator, or table functions. Key novel characteristics of YeSQL include easy implementation of complex algorithms and several performance enhancements, including tracing JIT compilation of Python UDFs, parallelism and fusion of UDFs, stateful UDFs, and seamless integration with a database engine. Experimental analysis showcases the usability and expressiveness of YeSQL and demonstrates that its techniques of minimizing context switching between the relational engine and the Python VM are very effective and achieve significant speedups of up to 68x in common, practical use cases compared to earlier approaches and alternative implementation choices.