Getting All Keys Starting With a Specific Pattern in Redis Using Java (Detailed Guide w/ Code Examples)

Use Case(s)

In many instances, we may need to retrieve all keys from a Redis database that begin with a specific string. This is particularly useful when you're dealing with a large amount of data and keys are grouped by certain prefixes.

Code Examples

The following example demonstrates how to get all keys starting with a specific pattern using Jedis, a popular Redis Java client:

import redis.clients.jedis.Jedis;

public class Main {
    public static void main(String[] args) {
        Jedis jedis = new Jedis("localhost");
        Set<String> keys = jedis.keys("pattern*");
        for (String key : keys) {
            System.out.println(key);
        }
    }
}

In this code, jedis.keys("pattern*") retrieves all keys starting with 'pattern'. The returned keys are printed out using a simple loop.

Best Practices

When using the KEYS command in production environments, be careful as it might affect performance when run against large databases. For improved performance, consider using the SCAN command instead.

Common Mistakes

A common mistake is to use wildcard queries on a large dataset in a production environment. This can lead to performance issues because the KEYS command works in a blocking manner and can potentially block other operations until it's done.

FAQs

Q: Can I use patterns other than the prefix pattern? A: Yes, any glob-style pattern supported by Redis can be used with the keys method.