PHP development: How to use Memcached caching

In web development, it is often necessary to cache data. When data is updated frequently, using cache can greatly improve system performance. Memcached is a distributed memory caching system that can share cached data among multiple servers. This article will introduce how to use PHP to perform Memcached caching operations.

1. Install and configure Memcached server
Memcached server can be installed by downloading the binary installation package from the official website. After the installation is complete, configuration needs to be performed. The configuration file is in /etc/memcached.conf. You can modify the configuration file to specify the cache port number, cache capacity and other parameters. By default, the port number of Memcached is 11211.

2. Install and configure Memcached PHP extension
In PHP, you need to install the Memcached extension module to perform caching operations. The extension can be installed automatically by entering the command "pecl install memcached" in the terminal. After the installation is complete, you need to add configuration information to the php.ini file:

extension=memcached.so

3. Use Memcached to cache data
The following is the specific code implementation:

//Connect Memcached server
$memcached = new Memcached();
$memcached->addServer('127.0.0.1', 11211);

//Use cache
$key = 'cache_key';
$data = $memcached->get($key); //Get data from the cache
if (!$data) { //If there is no data in the cache , get it from the database and add it to the cache

$data = get_data_from_database();
$memcached->set($key, $data, 3600); //将数据存入缓存中，并设置有效时间为1小时

}

//Clear the cache
$memcached->delete($key);

The above code implements the operation of obtaining data from the Memcached cache. If there is no data in the cache, it obtains it from the database and then stores it in the cache. When using Memcached for caching, the cache validity period is usually set. After the cache expires, Memcached will automatically delete the cache.

4. Use Memcached to improve system performance
In actual work, we can use Memcached to cache some high-frequency data to improve the system's response speed and concurrency capabilities. For example, some frequently visited web pages and database query results can be stored in the cache, and the data can be obtained directly from the cache on the next visit, avoiding repeated queries to the database, thus improving system performance.

When using Memcached for caching, you need to pay attention to the following points:

1. Cache Key design: The cache Key needs to be unique to ensure the accuracy of the cached data;
2. Setting of cache time: The cache time needs to be set according to the actual situation. A cache time that is too short will increase the hit rate of the cache, and a cache time that is too long will cause the data to become outdated;
3. Memory allocation: when using Memcached needs to pay attention to memory allocation when caching. Excessive memory will cause server congestion and affect system performance.

In short, the performance of web application systems can be effectively improved by using Memcached caching. In actual development, the caching strategy needs to be reasonably designed and configured to maximize its effectiveness.

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