Performance Tuning Skill

When to use

• •When the user complains about "slow" endpoints.
• •When optimizing high-throughput features.
• •When code involves heavy computation or large data processing.

Tactics

1. Asynchronous Patterns

• •Promise.all: Run independent async tasks in parallel.
  typescript

  // Fast
  const [user, posts] = await Promise.all([getUser(id), getPosts(id)]);
  
  // Slow
  const user = await getUser(id);
  const posts = await getPosts(id);
  

2. Database Optimization

• •Indexing: Ensure WHERE, ORDER BY, and JOIN columns are indexed.
• •Select Fields: Only select the columns you need (select: { name: true }).
• •N+1 Problem: Use .include() or batch loaders (DataLoader) instead of looping queries.

3. Caching

• •Implementation: Use Redis for expensive query results or computed data.
• •Strategy: Cache-aside or Write-through depending on data freshness needs.

4. Node.js Specifics

• •Event Loop: Don't block it. Use setImmediate or Worker Threads for CPU tasks.
• •JSON: Serialization is expensive. Use fast-json-stringify (Fastify does this by default with schemas).

5. Memory Management

• •Streams: Use streams for large file processing instead of buffering into memory.
• •Leaks: Check for global listeners or uncleared intervals.