Multi Step Processes hard
Standard Sagas lack the 'Isolation' property of ACID transactions (ACD). What specific anomaly does this cause if two Sagas modify the same resource concurrently?
- A Deadlock.
- B Partition Tolerance failure.
- C Dirty Reads / Lost Updates: Because Sagas commit local transactions immediately, other Sagas can see (and modify) the intermediate state before the full workflow is complete.
- D Stack Overflow.
Answer: C. Dirty Reads / Lost Updates: Because Sagas commit local transactions immediately, other Sagas can see (and modify) the intermediate state before the full workflow is complete.
If Saga A reserves inventory but hasn't finished payment, and Saga B cancels that inventory reservation, Saga A might fail later because its data changed unexpectedly. Semantic Locking or TCC is required to fix this.
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