Deadlocks and the Terminator
What do deadlocks and the T-800 have in common?
One of my favorite action movies growing up was Terminator 2, where the resistance sends the T-800 back in time to save John Connor. Like the T-800, a deadlock in SQL Server can seem scary, but it’s a protector.
Deadlocks are a protective byproduct of SQL Server’s locking mechanisms and are resolved by the engine’s built-in deadlock detection logic. Deadlocks typically occur when locks are taken in an incompatible order, though other factors can also play a role. Without the deadlock mechanism, transactions could remain in contention indefinitely.
If you occasionally encounter a deadlock, SQL Server fulfills its role by selecting one transaction to roll back. However, the rolled-back transaction may fail to persist valuable data unless you implement retry logic.
Several methods can help reduce deadlocks, including ensuring proper indexes, accessing objects in a consistent order, and batching operations to reduce the number of locks taken. Additionally, you can always add retry logic to capture data effectively.
No, I didn't use ChatGPT to come up with this content, so if it's terrible, it's on me. However, I did use ChatGPT for the image.
