Characterizing and Predicting Bug Assignment in OpenStack

Open source software is becoming increasingly important in cloud computing. However, many cloud computing systems suffer from software bugs that cause significant dependability issues. Bug assignment and fixing are crucial parts of software maintenance to improve dependability. In this paper, we conduct an empirical study of 42,880 bug reports from OpenStack bug repository. We study the characteristics (e.g., distribution of bugs, distribution of assignees) of bug assignments in OpenStack and find the bug assignment pattern which we call as long tail. The findings can support the follow-up research on improving efficiency of bug assignment, that is, we propose a prediction method based on long tail model, and experimentally evaluate this method by applying it to OpenStack bug assignment.