Cache management in GraphQL

Introduction

Cache management helps store data temporarily to make fetching faster. It reduces waiting time when you ask for the same data again.

When you want to speed up repeated data requests in a GraphQL API.

When your app shows data that doesn't change often and you want to avoid asking the server every time.

When you want to reduce the load on your database by reusing stored results.

When you want smoother user experience by loading data quickly from cache.

When you want to control how long data stays fresh before updating it.

Syntax

GraphQL

cache: {
  keyArgs: [String],
  merge(existing, incoming) {
    return mergedData;
  },
  read(existing) {
    return data;
  },
  maxAge: Number
}

keyArgs defines which query arguments are used to identify cached data.

merge controls how new data is combined with existing cached data.

Examples

This example disables argument-based caching and merges lists by appending new items.

GraphQL

cache: {
  keyArgs: false,
  merge(existing, incoming) {
    return [...(existing || []), ...incoming];
  }
}

This example caches data based on the 'id' argument and returns cached data as is.

GraphQL

cache: {
  keyArgs: ['id'],
  read(existing) {
    return existing;
  }
}

This example sets cached data to expire after 60 seconds (60000 milliseconds).

GraphQL

cache: {
  maxAge: 60000
}

Sample Program

This example shows a simple cache configuration for user data. It merges new user data into the cache and reads it back. The maxAge sets cache expiry time (not used in this simple demo).

GraphQL

const cacheConfig = {
  keyArgs: ['userId'],
  merge(existing = [], incoming) {
    return [...existing, ...incoming];
  },
  read(existing) {
    return existing;
  },
  maxAge: 300000
};

// Simulate cache usage
let cache = [];

// Incoming data from server
const incomingData = [{ id: 1, name: 'Alice' }, { id: 2, name: 'Bob' }];

// Merge incoming data into cache
cache = cacheConfig.merge(cache, incomingData);

// Read data from cache
const cachedData = cacheConfig.read(cache);

console.log(cachedData);

Important Notes

Cache keys help identify which data belongs where in the cache.

Always think about how fresh your data needs to be when setting cache expiry.

Merging data properly avoids losing information when new data arrives.

Summary

Cache management stores data temporarily to speed up repeated requests.

Use key arguments to control how data is stored and retrieved.

Set expiry times to keep data fresh and avoid stale information.