Demystifying Databases: Correctness Anomalies Under Serializable Isolation

Most database systems support multiple isolation levels that enable their users to trade off exposure to various types of application anomalies and bugs for (potentially small) increases in potential transaction concurrency. For decades, the highest level of “bug-free correctness” offered by commercial database systems was “SERIALIZABLE” isolation in which the database system runs transactions in parallel, but in a way that is equivalent to as if they were running one after the other. We defined “serializable isolation” above as a guarantee that even though a database system is allowed to run transactions in parallel, the final result is equivalent to as if they were running one after the other.

Source: fauna.com