A characteristic study of performance bugs in application-database interactions

Environmental interactions (e.g., file I/O, network communication, database querying) are common bottlenecks of software applications. These interactions are also prone to performance bugs because developers may not understand the performance implication of the information sent to or from the environment (e.g., a database query sent to a database or a result set returned from the database). As a result, the performance bugs can further magnify the bottlenecks. Understanding the characteristics of these performance bugs is crucial for developers and testers to better address performance problems. Such understanding also provides guidance for researchers and tool vendors to develop effective tool support. However, there has been no study for understanding such characteristics in real-world software. To fill this gap, in this thesis, we present the first empirical study of bug reports for database-related performance bugs collected from popular real- world open-source projects (i.e., BugZilla, DNN, Joomla!, MediaWiki, Word- Press, Simple Machines, and Roundcube). We study common optimization opportunities, types of database-related performance bugs, and difficulties of fixing these bugs. Among the studied bug reports, we identify nine common bug types and seven common fix strategies. We also observe that bugs of certain types require more effort to diagnose and fix. Furthermore, we identify various opportunities for tool support to identify and diagnose these bugs