Searching for the performance bottleneck in an execution trace is an error prone and time consuming activity. Existing tools offer some comfort by providing a visual representation of trace for analysis. In this paper, the authors present the Stethoscope, an interactive visual tool to inspect and analyze columnar database query performance, both online and offline. Its unique interactive animated interface capitalizes the large data-flow graph representation of a query execution plan, augmented with query execution trace information. They demonstrate features of Stethoscope for both online and offline analysis of long running queries.