Exactly-Once Processing Is Easy. But Wait! My Bill Does Not Match My Order

Exactly-Once Processing Is Easy. But Wait! My Bill Does Not Match My Order

Speaker: Szymon Pobiega

 

Abstract:

No matter what technology vendors claim, the laws of the universe make exactly-once message delivery impossible. The only options we have are either losing messages (at-most-once) or getting duplicates (at-least-once). Let me suggest which one you should prefer: you don’t want to miss that one million dollar order and only figure it out when reading the logs two weeks later.

Join me in a journey to explore various ways of ensuring duplicates are properly detected and handled. In the end, losing and order is surely bad but you don’t want to fulfill that million-dollar order twice either, do you?

Along the way, we’ll look at natural idempotence of certain data structures, immutable data and identity-based de-duplication.