# GraphQL Optimization

> Techniques to solve the N+1 problem using Dataloader.

- Skill: `j4flmao/graphql-optimization` (Agent Skill)
- Install (CLI): `npx skillmds@latest add j4flmao/graphql-optimization`
- Raw SKILL.md: https://api.skillmd.com/api/skills/j4flmao/graphql-optimization/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Integrations & APIs
- Author: j4flmao (https://skillmd.com/u/j4flmao)
- Updated: 2026-09-21
- Page: https://skillmd.com/skills/j4flmao/graphql-optimization

---


# GraphQL Optimization: Solving N+1

## The N+1 Problem
Without optimization, fetching a list of items and their nested relations results in 1 query for the list and N queries for the relations. 

## Dataloader Solution
Dataloader batches and caches requests to the database.

## Diagram
```mermaid
%%{init: {"theme": "default", "flowchart": {"useMaxWidth": true}}}%%
graph TD
    A[Resolvers] -->|Individual Requests| B(Dataloader)
    B -->|Batched Request| C[(Database)]
    C -->|Batched Response| B
    B -->|Individual Responses| A
```

## Node.js Example (Dataloader)
```javascript
const DataLoader = require('dataloader');

const userLoader = new DataLoader(async (userIds) => {
    // Single DB query for all users
    const users = await db.query('SELECT * FROM users WHERE id IN (?)', [userIds]);
    // Ensure the results match the order of userIds
    const userMap = users.reduce((acc, user) => ({ ...acc, [user.id]: user }), {});
    return userIds.map(id => userMap[id]);
});

// In GraphQL Resolver
const resolvers = {
    Post: {
        author: (post) => userLoader.load(post.authorId)
    }
};
```