System Design Drill Day 12: The Saga Pattern for a Multi-Step Checkout
How sagas replace distributed transactions with local steps and compensations, using a multi-step checkout as the example.
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Posts tagged #distributed-systems
System Design Drill Day 11: The Transactional Outbox Pattern
Why writing to the database and pushing to a queue can't be atomic, and how a transactional outbox fixes lost and phantom events.
System Design Drill Day 10: Circuit Breakers, Timeouts and Degradation
How circuit breakers, timeouts and bulkheads keep a checkout alive when the payment gateway or SMS provider starts failing.
System Design Drill Day 9: Idempotency Keys for Payments and Retries
Why retries make duplicates inevitable, and how idempotency keys stop double charges and double stock decrements.
System Design Drill Day 8: Distributed Locks with Redis and Fencing Tokens
How distributed locks work with Redis SET NX EX, why leases and fencing tokens matter, and where locks fit in a checkout.
