Fuzz Testing Is the Best Thing To Happen to Our Application Tests

QuestDB, an open-source time-series database designed for high-performance workloads, has significantly improved its robustness by incorporating fuzz testing, an automated software testing technique that introduces unexpected or random data inputs to uncover bugs. Initially faced with challenges such as segfaults, data corruption, and concurrency issues, the QuestDB team implemented fuzz tests to address these problems, leading to a more stable database and a decrease in critical issues reported by the community. The fuzz tests, which include approaches like generation-based and mutation-based testing, have helped identify numerous bugs by applying randomness to various scenarios, especially in relation to the InfluxDB Line Protocol and SQL engine. The team also benefited from SQLancer, a tool for identifying logic bugs in SQL Database Management Systems, which reinforced their testing efforts. Through these methods, QuestDB has not only enhanced its own system but has also advocated for the use of fuzz testing across complex software applications to improve reliability and performance.