A Characteristic Study of Deadlocks in Database-Backed Web Applications

Deadlocks in database-backed web applications could involve different numbers of HTTP requests, and they could be caused by locks explicitly requested in application code or implicitly requested by databases during query execution. To help developers understand these deadlocks and guide the design of tools for combating these deadlocks, we conduct a characteristic study with 49 deadlocks collected from real-world web applications developed following different programming paradigms. We provide categorization results based on HTTP request numbers and resource types, with a special focus on cat-egorizing deadlocks on database locks. We expect our results to be useful for application developers to understand web-application deadlocks and for tool researchers to design comprehensive support for combating web-application deadlocks.