Search

Lessons (22)

• Consumers & Consumer Groups

  … Each partition is read by exactly one consumer in a group at a time. 2. One consumer can …

• Hash Maps & Sets

  … Grouping → map of lists Group anagrams: ["eat","tea","tan","ate","nat","bat"] → [["eat","tea","ate"],["tan","nat"],["bat …

• SQL Interview Query Drills

  … Find repeated rows SELECT name, section, COUNT( ) AS copies FROM students GROUP BY name, section HAVING COUNT( ) 1 …

• S — Single Responsibility Principle

  … accounting, marketing, the security team… "One reason to change" really means one group of people who would ask …

• Finding Service Boundaries with DDD

  … becomes one service (or a small group of services owned by one team). Each context: - Has its own …

• Normalization & Denormalization

  … If the keyboard is renamed, every historical line could be changed by mistake. ![Normal forms reduce a mixed …

• Which Pattern Do I Need?

  … Builder creates step by step . Observer vs Mediator Observer broadcasts one-to-many. Mediator coordinates many-to-many …

• Transactions, Indexes & Concurrency

  … What is a trigger? A trigger is database code automatically invoked by an INSERT, UPDATE or DELETE. It …

• Replication, Partitioning & Sharding

  … pieces Partition by time for events/orders, range for geography, or list for known groups. Good partitioning enables …

• Brokers, Replication & Durability

  … Brokers, leaders and followers, in-sync replicas, min.insync.replicas, leader election and KRaft, drawn step by step …

• Kubernetes Cluster Architecture

  … virtual clusters A namespace is a folder inside the cluster that groups resources and scopes names, permissions and …

• Kafka vs RabbitMQ & the Kafka Ecosystem

  … topic + partition by key Ordering Per queue (with one consumer) Per partition Throughput High (tens of thousands of …

• Topics, Partitions & Offsets

  … each partition can be read by a different consumer in a group. mermaid flowchart TB subgraph Topic["Topic …

• Helm, kubectl Cheat Sheet & Best Practices

  … Helm, the package manager The big idea Installing an app by hand means writing a Deployment, a Service …

• KISS: Keep It Simple, Stupid

  … It's fun to watch, and it breaks if one domino is off by a millimetre. A light …

• Layered (N-Tier) Architecture

  … migrations/] Vertical slice architecture (a later lesson) groups code by feature instead, to fix this. Folder structure text …

• Graphs: BFS & DFS

  … stations are connected by lines. Some stations connect to many others; you can often reach a station by …

• What Is Software Architecture?

  … Architecture is mostly driven by these. Attribute Question Example requirement --- --- --- Performance How fast? p95 page load under 300 …

• REST API Design

  … items are grouped logically, named clearly, and ordering works the same way for every dish. Once you've …

• Sorting Algorithms

  … Sort users by city with a stable sort and, within each city, they stay in their previous order …

• Caching & Redis

  … check cache → DB on miss → store with a TTL. - Invalidate by TTL, by deleting on write, or through …

• Domain-Driven Design: Tactical Patterns

  … the consistency boundary ⭐ An aggregate is a group of entities and value objects that must stay consistent together …