Jayant Haritsa (IISc Bangalore): Shedding Light on Opaque Database Queries

Shedding Light on Opaque Database Queries

location:

Donald Bren Hall 3011

Speaker:  Jayant Haritsa

                 Database Systems Lab

                 Indian Institute of Science, Bangalore

Abstract: We have recently defined a new query reverse-engineering problem of unmasking SQL queries hidden within opaque database applications. The diverse industrial use-cases for this problem range from resurrecting legacy code to query rewriting.  It poses hard and novel intellectual challenges due to the presence of a variety of complexities such as dependencies between the query clauses, schematic renaming in the output attributes, result consolidation due to aggregates, and presence of computed column functions.

In this talk, we motivate the hidden query extraction problem, and then present UNMASQUE, an extraction algorithm based on an active learning approach, that successfully exposes a complex class of hidden warehouse queries. A special feature of its design is that the extraction is completely non-invasive with respect to the application, examining only the results obtained from repeated executions on databases derived with a combination of data mutation and data generation techniques. Further, potent optimizations are incorporated to minimize the extraction overheads. A detailed evaluation over applications hosting hidden SQL queries, or their imperative versions, demonstrates that UNMASQUE correctly and efficiently extracts these queries.

While the above represents a first step in query extraction, a suite of open research problems that remain to be solved will be covered at the end of the talk.

Bio: Jayant Haritsa is on the computer science faculty at the Indian Institute of Science, Bangalore, since 1993. He received a BTech degree from the Indian Institute of Technology (Madras), and MS and PhD degrees from the University of Wisconsin (Madison).  He is a Fellow of ACM and IEEE, and currently the President of ACM India.