--- title: "When Good Locks Go Bad: Diagnosing a System Meltdown Under Load" url: https://daily.dev/posts/when-good-locks-go-bad-diagnosing-a-system-meltdown-under-load-evp32lkxu source_url: https://blog.flipkart.tech/when-good-locks-go-bad-diagnosing-a-system-meltdown-under-load-0b168c363143 type: article source: "Flipkart Tech" published: 2025-11-10T16:26:19.947Z updated: 2025-11-10T16:26:47.644Z tags: ["performance", "kubernetes", "redis", "distributed-systems"] reading_time: 17 upvotes: 10 comments: 0 language: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # When Good Locks Go Bad: Diagnosing a System Meltdown Under Load **[Flipkart Tech](https://daily.dev/sources/flipkart)** · 17 min read · 10 upvotes · 0 comments ## Summary Engineers at Flipkart diagnosed a critical system failure during load testing for their Big Billion Days sale. Their Mirana service crashed under load due to excessive contention on a Redis distributed lock. Initial solutions using queuing failed because they violated the 'fail fast' principle. The team ultimately solved the problem by implementing an AtomicInteger-based semaphore to limit concurrent threads attempting lock acquisition. The key insight was optimizing for actual service performance (200-300ms per request) rather than downstream resource limits, reducing allowed concurrency from 128 to 5 threads per pod and achieving stable throughput of 90 QPS across 9 pods. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [The Great Connection Pool Meltdown](https://daily.dev/posts/the-great-connection-pool-meltdown-uejdycz6g) · Jacob’s Tech Tavern · 28 upvotes · 0 comments - [We replaced Redis with MySQL for inventory reservations—and it scaled \(2026\)](https://daily.dev/posts/we-replaced-redis-with-mysql-for-inventory-reservations-and-it-scaled-2026--7uecbcooa) · Hacker News · 1 upvotes · 0 comments --- Tags: [#performance](https://daily.dev/tags/performance), [#kubernetes](https://daily.dev/tags/kubernetes), [#redis](https://daily.dev/tags/redis), [#distributed-systems](https://daily.dev/tags/distributed-systems) [View this post on daily.dev](https://daily.dev/posts/when-good-locks-go-bad-diagnosing-a-system-meltdown-under-load-evp32lkxu)