Database Management Systems (DBMSs) utilize transactions to guarantee data consistency and integrity. Incorrect implementations of transaction processing mechanisms can introduce critical transaction bugs, which can lead to incorrect database states after the involved transactions complete. However, we lack an effective test oracle to determine whether a DBMS produces a correct database state for a given concurrent transaction schedule. In this paper, we propose a general property for concurrent transaction schedules, write-specific serializability , in which a schedule of concurrent transactions should produce the same database state as a corresponding serial schedule of the same transactions. Through our empirical study on 35 critical transaction bugs collected from six widely-used DBMSs, we find that write-specific serializability can be an effective test oracle to expose critical transaction bugs in DBMSs. We further develop a simple and general transaction testing approach, WriteCheck, to automatically detect write-specific serializability violations by identifying inconsistencies in the final database states produced by the original transaction schedule and its corresponding serial schedule. We evaluate WriteCheck on the latest versions of six production-grade DBMSs, and have found 22 write-specific serializability violations, 11 of which have been confirmed as new critical transaction bugs.

Transactions are used to guarantee data consistency and integrity in Database Management Systems (DBMSs), and have become an indispensable component in DBMSs. However, faulty designs and implementations of DBMSs' transaction processing mechanisms can introduce transaction bugs, and lead to severe consequences, e.g., incorrect database states and DBMS crashes. An in-depth understanding of real-world transaction bugs can significantly promote effective techniques in combating transaction bugs in DBMSs.