KEYS pattern matching (avoid in production) in Redis

Introduction

The KEYS command helps find all keys in Redis that match a pattern. It is like searching for files by name on your computer.

When you want to see all keys that start with a certain word.

When you need to find keys containing a specific part in their name.

When you want to check what keys exist during development or debugging.

When you want to clean up keys matching a pattern in a test environment.

Syntax

Redis

KEYS pattern

The pattern can include * as a wildcard to match any characters.

Avoid using KEYS in production because it can slow down Redis if many keys exist.

Examples

Finds all keys that start with 'user:'

Redis

KEYS user:*

Finds all keys that contain 'session' anywhere in their name

Redis

KEYS *session*

Finds all keys in the database

Redis

KEYS *

Sample Program

This example sets three keys and then finds all keys starting with 'user:'.

Redis

SET user:1 Alice
SET user:2 Bob
SET session:123 active
KEYS user:*

Important Notes

The KEYS command scans all keys, so it can be slow if you have many keys.

Use SCAN command in production for safer, incremental key searching.

Common mistake: Using KEYS on a large database can cause Redis to freeze temporarily.

Summary

KEYS finds keys matching a pattern using wildcards.

It is useful for quick checks or debugging.

Avoid KEYS in production; prefer SCAN for large datasets.