redis delete keys that match pattern with code examples

redis-cli KEYS "mypattern*" | xargs redis-cli DEL

import redis

r = redis.Redis(host='localhost', port=6379, db=0)
keys = r.keys('mypattern*')

for key in keys:
    r.delete(key)

import redis.clients.jedis.Jedis;

Jedis jedis = new Jedis("localhost");
Set<String> keys = jedis.keys("mypattern*");
for (String key : keys) {
    jedis.del(key);
}
jedis.close();

const Redis = require("redis");
const redisClient = Redis.createClient();

redisClient.keys("mypattern*", (err, keys) => {
    keys.forEach(key => {
        redisClient.del(key);
    });
});

$redis = new Redis();
$redis->connect('127.0.0.1', 6379);

$keys = $redis->keys("mypattern*");
foreach ($keys as $key) {
    $redis->del($key);
}

require 'redis'

redis = Redis.
Sure, let's continue with some additional information on related topics.

## Key Expiration

In Redis, keys can have an optional time-to-live (TTL), after which they will automatically be deleted. This is a useful feature when working with keys that have a limited lifespan, such as session keys or cache keys. To set a TTL on a key, you can use the `EXPIRE` command. For example:

In this example, the key `mykey` has been set with the value `"Hello, Redis!"` and a TTL of 30 seconds. After 30 seconds, the key will be automatically deleted.

It's important to note that setting a TTL on a key does not guarantee that it will be deleted exactly after the specified time. The key may persist for a few seconds longer or be deleted a few seconds sooner, depending on various factors such as Redis configuration and system load.

## Batch Deleting Keys

In some cases, you may need to delete a large number of keys at once. When dealing with large datasets, it's not recommended to delete keys one by one, as this can cause performance degradation. To optimize key deletion, Redis provides the `UNLINK` command, which allows you to delete multiple keys in a single operation. For example:

In this example, the `MSET` command is used to set multiple keys at once, and the `UNLINK` command is used to delete all three keys in a single operation. This can be more efficient than deleting keys one by one, especially when dealing with large datasets.

## Conclusion

In this article, we have discussed how to delete Redis keys that match a pattern, along with code examples in several programming languages. We have also explored the concept of key expiration and batch deleting keys. By using the techniques and examples presented in this article, you can effectively manage your Redis keys and keep your data optimized.
## Popular questions 
Sure, here are five questions and answers related to deleting Redis keys that match a pattern:

1. How can I delete Redis keys that match a pattern using the Redis command line interface?

You can use the `KEYS` command to retrieve all keys that match a pattern, and then use the `DEL` command to delete each key. For example:

In this example, the `KEYS` command is used to retrieve all keys that match the pattern `mypattern*`, and the `xargs` utility is used to pass the list of keys to the `DEL` command.

2. Can I delete Redis keys that match a pattern using a programming language?

Yes, you can use a Redis client library for your programming language of choice to delete Redis keys that match a pattern. For example, in Python, you can use the `redis-py` library to delete keys that match a pattern:

In this example, the `redis-py` library is used to connect to a Redis server and retrieve a list of keys that match the pattern `mypattern*`. Then, the `delete` method is used to delete each key in the list.

3. What is the performance impact of deleting Redis keys that match a pattern?

The performance impact of deleting Redis keys that match a pattern depends on the number of keys that need to be deleted and the size of the keys and values. Deleting a large number of keys can cause performance degradation, as Redis needs to update its internal data structures and reclaim the memory used by the deleted keys. To minimize the performance impact, it's recommended to use a batch deletion technique, such as the `UNLINK` command or the equivalent batch deletion operation in your programming language of choice.

4. Can I undo a Redis key deletion operation?

No, once a Redis key has been deleted, the operation cannot be undone. Redis does not have a built-in mechanism for undoing key deletions. If you need to preserve deleted keys, you should implement a backup mechanism, such as storing deleted keys in a separate Redis database or dumping the deleted keys to a file.

5. Is it possible to delete Redis keys that match a pattern in a transaction?

Yes, it's possible to delete Redis keys that match a pattern in a transaction. A Redis transaction is a series of commands that are executed as a single, atomic operation. To delete keys that match a pattern in a transaction, you can use the `MULTI` and `EXEC` commands to wrap the key deletion operations. For example:

In this example, the `MULTI` command is used to start the transaction, the `KEYS` and `DEL` commands are used to delete the keys that match the pattern `mypattern*`, and the `EXEC` command is used to execute the transaction. This ensures that all key deletion operations are executed as a single, atomic operation, without any other
### Tag 
Redis-Deletion