01 · Context
The exam system needs low-latency question reads and answer autosaves. The previous S3-first hot path increased response time as concurrent participation grew.
Technical case study
Redis-first exam flow
Optimizing question reads and autosave hot paths while preserving durable persistence.
LaravelRedis HashQueueS3k6Distributed lock
02 · Problem
Reduce latency for getQuestions and save, prevent duplicate exam creation, and retain a reliable fallback and durable persistence path.
03 · Architecture
Processing flow
01 Exam request
02 Distributed lock
03 Redis Hash
04 Persist queue
05 S3 storage
04 · Result
In a controlled 25-VU benchmark, throughput improved by about 6.1×; getQuestions p95 dropped by roughly 69% and save p95 by roughly 70% versus the S3-first flow.
05 · Ownership
I directly designed, implemented and benchmarked the Redis-first flow.
06 · Trade-off
A faster Redis hot path requires explicit fallback, rebuild and persistence strategies. Queue failures need retries and monitoring, and benchmark numbers must not be presented as production SLAs.
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