Before we look at the different types of caching, we need to fully understand what caching is. You can use a cache to store information for a fixed period of time on a computer. Caching is used to reduce the time it takes to access data on a website. As such, caching is used to improve the performance of any website and application.
There are various types of caching including client-side and server-side. To start we’ll look at caching on the user end side aka client-side caching.
Client-side caching is used for storing data files that could be useful to the user on their personal computer. Though there are various types of client-side caching, browser cache is the one we’ll explore below.
We all have our favorite websites that we visit regularly. Browser caching makes things easy and much faster for you because rather than requesting and transmitting the data required for that website to display on your browser, it is instead stored on your computer. That way, website loading times are a lot faster, and data from the site can be accessed almost immediately. All of the major web browsers from Google Chrome to Firefox uses browser caching.
Individual users are able to alter the settings within their browser to change or modify the cache. The cached files are stored directly on the computer and takes up disk space. As such, they can be emptied or removed completely. The important factor to understand is that this type of client-side caching can reduce load times by at least a few factors.
Now that you have an understanding of client-side caching, we will now look at server-side caching. With server-side caching, data is cached on the server. Data can be cached at any point or time on the server when it makes sense. Recent images and files viewed from the internet will be stored on the server. Clients can then access the information more quickly, again improving the user experience.
This process can be included in the design of a web application that generate data on websites with databases. This is used to achieve better performance and higher scalability.
Database caching provides a variety of advantages for web developers. The most important factors is that it reduces disk access, reduces cpu utilization, and speed up the time it takes to access data.
With object caching, an object data can be stored locally so that it doesn’t have to be constantly retrieved for additional requests. As such, it increases the speed and performance of a web application. An object is a collection of data that include word documents, videos or images. If the object is cached when a user requests the information, it can be transferred directly from the local cache, rather than requesting it from the server.
This is the main benefit of object caching. If users are requesting data that is unchanged, they can access it without using the server, making things a lot easier, and faster. As such users aren’t left waiting for the content to load, and bandwidth isn’t wasted.
To enhance the performance of PHP you need opcode cache. Opcode cache keeps a copy of the PHP opcode in server memory for when they could be needed later. Doing this, it is possible to increase PHP performance by 3 times.
Opcode caches have no side effects at all except for additional usage of memory. As such, they are recommended for any and all production environments. They are a fantastic way of boosting your PHP and is certainly an extension worth adding.
There are a number of different opcode caches. The first one developed for PHP was Zend. Starting with version 5.5, Zend is now included with PHP by default known as Zend Opcache. Prior to 5.5, most sites are using Alternative PHP Cache (APC). APC is an effective PHP cache, although it does not have some of the benefits provided by Zend.
The New Zend Opcache misses out on a key shared memory cache feature provided by APC. As such, a new APC extension called APCu was released with just a memory cache to boost PHP performance.
Page cache is similiar to the other caches with the benefits being faster page load speed for a better user experience. The page cache stores full web pages to be served at a later time to the visitor. This data is stored in an unused section of RAM and thus have no real impact on memory. In fact, despite being used to store this information, the computer might still register this section of the computer memory as available or even free. If the data is read again later, it will be read from this cache within memory.
Content Delivery Network (CDN) Cache
CDN caching is a broader form of data storage. With CDN caching, static website content is added to proxy servers that are globally distributed. This allow your visitors from all over the world to download your site content faster thus speeding up your site load time.
CDN caching also helps website owners reduce costs, takes pressure off the original server, and puts the focus on the smaller local servers located globally where your visitors can access data locally.
We hope you find the information provided here on the various types of caches both useful and informative.