Database engines and database-centric applications have become complex software systems. Ensuring bug-free database services is therefore a very difficult task. Whenever possible, bugs that are uncovered during testing are associated with a repro, or sequence of steps that deterministically reproduce the problem. Unfortunately, due to factors such as automated test generation, repros are generally too long and complex. This issue prevents developers reacting quickly to new bugs, since usually a long manual “repro-minimization” phase occurs before the actual debugging takes place. In this paper we present a fully automated technique to minimize database repros that leverages underlying language grammars and thus is significantly more focused than previous approaches. Our approach has been successfully used in two com-
mercial database products to isolate and simplify bugs during early development stages. We show that our technique consistently results in repros that are as concise or simpler and obtained much
faster than alternative ones carefully constructed manually.