Transaction isolation levels: the trade-off between speed and data safety in Django

Database transactions carry an isolation level setting that controls how much overlapping transactions can see of each other's unfinished work. Lower levels run faster but can expose incorrect or temporary data, while higher levels keep data more reliable at the cost of performance and more conflicts. The article explains three anomalies that can occur when transactions overlap: dirty reads, non-repeatable reads, and phantom reads. It also outlines four isolation levels that each block progressively more of these problems, along with Django's default and the situations where changing it makes sense.