AnhDH.

Start here

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. 1Message BrokerHave you ever wondered what keeps payment services, social networks, and delivery apps running smoothly every single day? The secret lies in the Messa…
  2. 2Distributed Locks and How to Implement Them with RedisIn distributed systems, ensuring data consistency and preventing race conditions is a major challenge, especially when many processes or services acce…

Databases

  1. 1COUNT(*) vs COUNT(1): Which One Performs Best?When counting rows in a table, we reach for the count function out of habit. But the count function accepts several kinds of arguments, such as count(…
  2. 2What Happens When MySQL Executes a SELECT Query?SELECT is usually the very first SQL statement anyone learns, yet few stop to ask what actually happens inside MySQL when that statement runs. This po…

Operations & tooling

  1. 1CronJob & Cron ExpressionsCronJob is an essential tool that lets developers automate tasks on a recurring schedule. To configure a CronJob correctly, however, you need a solid…
  2. 2Basic Linux TerminologyBefore getting anywhere near Kubernetes itself, the story has to start with the foundation of everything in this series: the Linux kernel. If you've n…
  3. 3Physical Servers and Their LimitsWhat does a physical server actually look like, and why can't we just keep deploying more onto the same one?
  4. 4Virtual MachineHow does the Virtual Machine solve the physical server's "one machine, one environment" problem, and what does this approach cost you?
  5. 5ContainerThe container solves the Virtual Machine's weight and boot-time problem by dropping the private kernel every VM has to carry around.
  6. 6Kubernetes Cluster ArchitectureWhat actually makes up a Kubernetes cluster? The control plane decides what runs where, the nodes run it, and the addons fill in the rest.

Backend

  1. 1Top 10 Java Core Interview QuestionsFoundational knowledge is something interviewers always check, whether you're a fresher or a senior engineer. This post rounds up the 10 most common J…
  2. 2C4 Model: Visualizing Software ArchitectureYour architecture diagram has 40 boxes, 200 arrows, and nobody understands it. The C4 model fixes that with four zoom levels — like Google Maps for yo…