The document discusses various aspects of data migration and concurrency in software applications, highlighting two cases involving data handling strategies. It emphasizes the importance of locking mechanisms, such as pessimistic and optimistic locks, and best practices to avoid common concurrency issues like deadlocks. Guidelines for managing thread interactions and mutable data sharing in JRuby are also provided.

1. @jaisonerick
@jonatasdp
hosted by supported by
Concurrency

2. Concurrency

3. Case 1:
Migrating DATA

4. Migrating DATA
Case da BONUZ
(@jaisonerick)

5. Migrating DATA
Case da Resultados Digitais
(@jonatasdp)

6. Case 2:
BONUZ
WEB APPLICATIONS

7. Pessimistic Optimistic

8. MODE
● SHARED
● EXCLUSIVE

9. Exclusive Pessimistic Lock
SELECT * FROM `accounts` where `id`=1 FOR UPDATE;

10. Shared Pessimistic Lock
SELECT * FROM `accounts`
where `id`=1 LOCK IN SHARE MODE;

11. Item Model:
Item Controller:

12. Threads
● MUTEX
● DEAD LOCK

13. Encapsulated

15. Always lock in the
same order!

16. ● Don't do it, if you can avoid it.
● If you must do it, don't share data across
threads.
● If you must share data across threads, don't share
mutable data.
● If you must share mutable data across threads,
synchronize access to that data.
JRUBY - Concurrency Rules:

17. Testing Concurrency
...with concurrency

19. Hands On!

20. Perguntas?