AnhDH.

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New here? This is the curated path through my writing — the posts I'd hand someone who wants the most signal, fastest.

Distributed systems

  1. 1Distributed Locks and How to Implement Them with RedisWhen correctness depends on one writer at a time — and how to build a lock with Redis.
  2. 2Message BrokerHow asynchronous messaging keeps services decoupled, resilient, and scalable.

Databases

  1. 1understanding-database-indexesWhat an index really is, and how it turns a full scan into a lookup.
  2. 2COUNT(*) vs COUNT(1): Which One Performs Best?A myth-busting look at COUNT(*) vs COUNT(1) performance.

Operations

  1. 1CronJob & Cron ExpressionsSchedule recurring work correctly — read cron expressions with confidence.