Enabling intensional access control via preference-aware query optimization

Although the declarative nature of SQL provides great utility to database users, its use in distributed database management systems can result in unintended consequences to user privacy over the course of query evaluation. By allowing users to merely say what data they are interested in accessing without providing guidance regarding how to retrieve it, query optimizers can generate plans that leak sensitive query intension. To address these types of issues, we have created a framework that empowers users with the ability to specify access controls on the intension of their queries through extensions to the SQL SELECT statement. In this demonstration, we present a version of PostgreSQL's query optimizer that we have modified to produce plans that respect these constraints while optimizing user-specified SQL queries in terms of performance.