Node Redis: Get Multiple Keys (Detailed Guide w/ Code Examples)

Use Case(s)

MGET is a command in Redis that allows you to retrieve multiple keys in a single operation, which can be useful when you need to fetch many values simultaneously, improving the efficiency over separate GET operations.

Code Examples

Example 1: Basic usage of MGET with Node.js and redis package.

const redis = require('redis');
const client = redis.createClient();

client.mget(['key1', 'key2', 'key3'], function(err, reply) {
    console.log(reply);  // Prints an array of values for 'key1', 'key2', and 'key3'
});

In this example, we create a Redis client and use the mget method to get the values of 'key1', 'key2', and 'key3'. The result is an array containing the value of each key.

Example 2: Handling missing keys.

const redis = require('redis');
const client = redis.createClient();

client.mget(['missingKey', 'anotherMissingKey'], function(err, reply) {
    console.log(reply);  // Prints: [ null, null ]
});

In this example, if a key doesn't exist in the Redis store, mget returns null for that key.

Best Practices

• Use MGET over individual GET commands when you need to retrieve multiple keys at once. It reduces network latency and improves performance.

Common Mistakes

• Not checking for null values in the result array. MGET returns null for keys that do not exist.

FAQs

Q: Can I mix existing and non-existing keys while using MGET?

A: Yes, MGET will return an array with the values of existing keys and null for non-existing keys.