How to enable Memcached in WordPress to improve website speed

Memcached memory caching can optimize many functions of WordPress and make your WordPress faster. The following column WordPress Tutorial will introduce how to use Memcached to deeply optimize WordPress.

Many people ask me how to make WordPress fast. Usually the simple answer is to install Memcached. This is really not a perfunctory task. It is not an exaggeration. Installing Memcached can make WordPress faster. It is several times faster, but to really use WordPress well, you still need to have a deeper understanding of WordPress, so I have reorganized all the articles on my blog about Memcached and made a special collection of in-depth optimization of WordPress so that everyone can truly understand WordPress optimization.

What is Memcached?

Memcached is a high-performance distributed memory object caching system. Using Memcached in dynamic programs can not only increase the access speed, but also reduce the load on the database.

Memcached can store any type of data (strings, objects) generated from calling databases and APIs, or page rendering into memory, or it can be read directly from memory. Its API supports most of the currently popular programming languages. Memcached's official website: http://memcached.org/

Initially Danga Interactive developed Memcached to improve the speed of LiveJournal.com. At present, it has finally been implemented It is already providing up to 20 million page views to one million users every day, and these are completed by a cluster composed of Web servers and database servers.

Memcached PHP Extensions

PHP has two Memcached extensions: "PHP Memcache Extension" and "PHP Memcached Extension", and this is where we get confused.

PHP Memcache extension is implemented in PHP and supports both object-oriented and process-oriented interfaces. It was implemented in 2004. It is an old extension with few functions and few attributes that can be set.

PHP Memcached extension is developed based on libmemcached. It uses the API provided by the libmemcached library to interact with the Memcached service. It only supports object-oriented interfaces and was only implemented in 2009. The Memcached extension function is more complete and supports more functions. For example, to support batch operations, it is generally recommended to use the Memcached extension.

The following is a comparison list of supported functions:

##Memcached can greatly improve the efficiency of WordPress

Since WordPress supports Object Cache by default, the implementation of Memcached in WordPress is to use Memcached to write the WordPress Object Cache into the memory, and read it directly from the memory the next time it is accessed. Compared with reading data directly from the database, or saving data from Object Cache to a file, and then reading it from the hard disk, Memcached has a great speed advantage.

The picture above is the hit rate of the cached object after I Love Boiled Fish uses Memcached. It can be seen that the hit rate is very high, close to 99%, which is basically guaranteed. All data is retrieved from memory, so caching using Memcached is very effective.

How to enable Memcached caching in WordPress

First of all, it needs to be clear that the Memcached server and its PHP extension must be installed at the same time.

If the Memcached server is installed and the extension is not installed, PHP cannot control Memcached. Similarly, if the PHP Memcached extension is installed but the Memcached server is not installed, then this cannot be used.

1. First, the server needs to install the Memcached server, and then PHP needs to install the Memcached extension. Note again that PHP has two extensions: PHP Memcache extension and PHP Memcached extension. The difference between the two is only one letter D. You You can use the phpinfo() PHP function to check which extension is installed. Be sure to use the PHP Memcached extension.

2. The WPJAM Basic plug-in has integrated the function of Memcached. Copy the object-cache.php file in the wpjam-basic/template/ directory to the wp-content directory. Note that it is not wp-content/plugins/.

3. WordPress will automatically check whether there is an object-cache.php file in the wp-content directory. If there is, call it directly as the WordPress object caching mechanism.

4. After successful installation, WPJAM Basic will automatically see Memcached information under "System Information" under the WordPress > WPJAM menu:

WPJAM Basic plug-in has integrated Memcached. After downloading WPJAM Basic, copy the object-cache.php file in the wpjam-basic/template/ directory to the wp-content directory.

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