Clear all cached data in Redis from PHP

For developers who use Redis as a cache server, it is very necessary to regularly clear the cache data in Redis. If the cached data saved in Redis is not cleared for a long time, it will occupy a large amount of memory resources, reduce system performance, and may even cause the system to crash. This article will explain how to clear all cached data in Redis using PHP code.

1. Redis Cache Cleaning

Redis provides a variety of methods for clearing cache data. The specific method is selected according to the actual application scenario of the developer. Commonly used methods include:

1. FLUSHALL command

Use the FLUSHALL command to clear all key-value pairs in the Redis database.

Syntax: FLUSHALL [ASYNC]

Parameter description:

The ASYNC option is optional, indicating that the clearing operation is performed asynchronously and does not block other operations of the current Redis server. However, it should be noted that the ASYNC option may cause certain data loss, so the choice needs to be made based on the actual scenario.

Sample code:

$redis = new Redis();
$redis->connect('127.0.0.1', 6379);
$redis->flushAll(); //清除Redis中所有缓存数据

2. KEYS command

Use the KEYS command to obtain all keys that match the specified pattern in the Redis database, and then use the DEL command Delete one by one.

Syntax: KEYS pattern

Parameter description:

pattern represents the pattern and supports wildcards.

Sample code:

$redis = new Redis();
$redis->connect('127.0.0.1', 6379);
$keys = $redis->keys('*'); //获取所有键名
foreach ($keys as $key) {
    $redis->del($key); //逐个删除
}

3. Category clear

For the key of a certain category, use the following command:

$redis = new Redis();
$redis->connect('127.0.0.1', 6379);
$keys = $redis->keys('prefix:*'); //获取指定模式键名
foreach ($keys as $key) {
    $redis->del($key); //逐个删除
}

2. How to clear Redis cache data in PHP

In PHP, we can use the API provided by the Redis extension library to interact with the Redis server. The specific steps are as follows:

1. Connect to the Redis server

Use the connection method provided by the Redis extension library to connect to the Redis server. After the connection is successful, you can interact with the Redis server. The connection method is as follows:

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

2. Clear cached data in Redis

Choose to clear all cached data in Redis or cached data of specified categories according to actual needs.

The method of clearing all cached data is as follows:

$redis->flushAll();

The method of clearing the cached data of a specified category is as follows:

$keys = $redis->keys('prefix:*'); //获取指定模式键名
foreach ($keys as $key) {
    $redis->del($key); //逐个删除
}

3. Close the Redis connection

After completing the Redis operation, you need to use the following method to actively close the connection with the Redis server:

$redis->close();

3. Precautions

1. Be careful about data loss

Be careful when using the FLUSHALL command. This command can quickly clear all cached data in Redis, but it may also cause data loss. If the reliability of the data is high, it is recommended to use the KEYS command to clear cached data one by one.

2. Pay attention to the life cycle of cached data

Regularly clearing the cached data in Redis requires determining the clearing interval based on the actual situation. If the clearing interval is too short, cached data will be cleared frequently, reducing system performance; if the clearing interval is too long, cached data will expire, increasing system operating costs.

3. Pay attention to the security of the code

Special attention should be paid to the fact that when using the code to clear the cache data, you need to carefully verify the security of the code. The execution of the clear cache command requires sufficient permissions. If the security check of the code is not strict, it may lead to the leakage and damage of system data.

4. Summary

This article introduces the method of using PHP code to clear all cached data in Redis, mainly including three methods: FLUSHALL, KEYS and deleting cached data one by one. When using these methods to clear cached data in Redis, you need to pay attention to issues such as data reliability, cached data life cycle, and code security. In actual applications, developers need to choose the appropriate removal method according to the specific situation and conduct sufficient testing and verification.

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