The Pragmatic Programmer - Chapter 6: Concurrency

• Concurrency: when the execution of 2 or more pieces of code act as if they run at the same time. -> Software layer
• Parallelism: when they do run at the same time. -> Hardware layer

Breaking Temporal Coupling

• Analyse workflow to improve concurrency.
  • It helps to see what is dependent or not. Points of parallelism.

Shared State Is Incorrect State

• Making a operation atomic:
  • Semaphores
  • Make the resource transactional
• Whenever 2 or more instances of the code can access some resource at the same time, you are looking at a potential problem.
• Random failures are often concurrency issues!

Actors and Processes

• Use actors for concurrency without shared state.