What are the comparisons between Haskell's STM and other concurrency models?

What are the comparisons between Haskell's STM and other concurrency models?

Haskell's Software Transactional Memory (STM) offers a unique approach to concurrency, focusing on composability and ease of reasoning. Unlike traditional locking mechanisms, STM allows for transactions that can be retried in case of conflicts, which can lead to more robust and maintainable code. In comparison, models like threads and locks can lead to deadlocks and race conditions.

Can you explain how STM handles conflicts?

STM handles conflicts by using a retry mechanism. When a transaction detects that another transaction has modified a variable it depends on, it can automatically retry the operation. This ensures that transactions are isolated and consistent without the need for explicit locking.

What are the advantages of using STM over traditional locking?

The advantages of using STM include improved composability, reduced risk of deadlocks, and easier reasoning about concurrent code. Since transactions can be retried, developers can focus on the logic rather than managing locks.

Are there any downsides to using STM?

Yes, while STM simplifies concurrency, it can introduce overhead due to the need for conflict detection and transaction management. In some cases, it may not perform as well as low-level locking mechanisms, especially in highly contended scenarios.