Asynchronous Processing for Coupon Issuance Using Redis Pub/Sub

Oliveyoung improved its existing Sync-based coupon issuance process to an Async approach in order to reduce user wait times during sale periods with massive traffic.

Initially, they adopted Redis Pub/Sub, but in a multi-Worker environment they experienced a coupon over-issuance problem caused by multiple Workers simultaneously receiving the same message, as well as a data loss problem caused by the lack of message delivery guarantees.

To solve this, they ultimately applied the following architecture:

• Redis Pub/Sub: Used to deliver signals for assigning tasks to a specific Worker
• Redis List: Functions as a queue that stores the actual coupon issuance data
• Worker logic: The assigned Worker checks the size of its own dedicated List, then safely processes the data by retrieving it via LPop

Through this structure, they built an environment capable of handling high traffic while issuing coupons stably without data loss.