Qunar 2020 Technical Article Collection: DDD, API, Backend, Infrastructure and System Design

In 2020, Qunar focused on strengthening internal technical capabilities, achieving notable results in business architecture based on domain‑driven design (DDD) and API construction, which received strong internal and external recognition.

The collection includes classic articles on DDD and API design, illustrating how Qunar reshaped its business under the guidance of "internal DDD, external API".

It also features high‑quality foundational technical articles produced in 2020, covering topics such as Linux disk I/O analysis, the seven‑layer network protocol, JVM memory model, and HotSpot Serviceability Agent (SA) principles.

Featured Articles:

• Hotel Pricing Refactoring Based on DDD – explains the strategic, tactical, and implementation phases of a DDD‑driven hotel pricing project.

• Design Philosophy of External APIs – shares Qunar's progress in API standardization in 2020.

• International Hotel Service Capability Enhancement (Parts I‑III) – discusses user‑centric service improvements for international hotel products.

• Domestic Hotel Architecture Optimization – outlines plans to decommission over 300 servers through architectural improvements.

• GraphQL in Hotel Systems – demonstrates how GraphQL boosts development and data transmission efficiency.

• Full‑Link Gray Release System – introduces a low‑cost, easy‑to‑implement gray‑release approach for accurate risk assessment.

• Redis Distributed Lock Solutions – compares various Redis‑based lock implementations and their trade‑offs.

• Business Gateway Implementation – describes Spring Cloud Gateway‑based design supporting multiple downstream protocols and visual configuration.

• Noah Environment Management Platform – explains the technical implementation of a testing environment governance platform.

• Qunar Lecture Hall Memory Leak Investigation – shares experience and lessons from diagnosing an online memory leak.

• Linux Disk I/O Principles (Part 1) – provides a macro view of disk I/O mechanisms, including cache, direct, PIO, interrupt, DMA, and mmap.

• Linux Network I/O Principles (Part 2) – explains network I/O architecture and zero‑copy concepts.

• Seven‑Layer Network Protocol Overview – details abstractions from the physical to transport layers.

• Java Serviceability Agent – explores how Java SA enables lightweight system diagnostics.

• Java Character Encoding – introduces character sets and encoding fundamentals.

• Evolution of JVM Heap Memory Models – compares traditional, G1, and low‑latency garbage collectors.

• Lucene Stored Fields Optimization – discusses mechanisms for efficient storage in Qunar's hotel search and suggestion system.

• International Hotel Aggregation Algorithm Optimization – presents algorithmic improvements for hotel aggregation across key countries.

The collection aims to help technology enthusiasts and professionals deepen their knowledge and apply these insights to improve system design, performance, and reliability.