hardLow-Level Design

Explain how memory management and Garbage Collection work in the V8 engine.

Q: Explain how memory management and Garbage Collection work in the V8 engine.

**TL;DR.** V8 manages a **heap** and reclaims unreachable objects with a **generational, mark-and-sweep** garbage collector. Objects start in a small **young generation** (Scavenge, very fast); survivors are promoted to the **old generation** (Mark-Sweep-Compact). The **generational hypothesis** — most objects die young — keeps GC cheap. young gen Scavenge — fast, frequent promote old gen</

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Understand the problem

Describe the generational strategy V8 uses to free up heap memory.

v8memorygarbage-collection

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Read the code

Inspect heap usage + raise the cap

const { heapUsed, heapTotal } = process.memoryUsage();
console.log((heapUsed / 1e6).toFixed(1), '/', (heapTotal / 1e6).toFixed(1), 'MB');

// Raise old-space limit (default ~2GB) at launch:
//   node --max-old-space-size=4096 server.js
// Expose manual GC for debugging only:  node --expose-gc  → global.gc()

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