What’s the Cache: From Web Cache to WordPress Caching and Beyond
What is a “web cache” and how does this affect WordPress caching on your website? Should you even care about web caching and the like?
Not to worry. These geeky concepts only matter if you want people to visit your website. (Sorry, couldn’t resist that…)
Why it matters… Most of your website’s audience would expect your site to load within 3 seconds. Unsurprisingly, Google keeps emphasizing website speed in its search algorithm as one of the important ranking factors.
One of the most beneficial technologies available, web caching improves website speed, making sites noticeably faster. Higher website speed ultimately leads to better SEO scores and higher user satisfaction, which results in better conversions. If you are selling products and services online, that equates to more revenue.
So, let’s see how a web cache can improve your website performance.
What is Web Caching Anyway?
A cache is a collection of temporary files used by devices to speed up or enhance the user experience. It is a way to temporarily store regularly accessed or reusable data.
Websites are visited hundreds and thousands of times a month. Each time a web page is requested by the browser, the server must perform a series of complex calculations that can be time-consuming.
It recovers the posts, finds sidebar widgets, generates header and footer, and many other tasks that involve fetching. In most cases, the end result will be the same. So, it would be easier and faster if the server remembers the final results and does not require to process each and every request separately.
This is exactly what caching does!
When the user visits your website, a cache takes a snapshot of your webpage. It then stores and serves the image to the visitor. So, when users make repeated requests with their browser, these requests are often fulfilled from a cache. There is no need to go to the server again to fetch every item all over again.
Web documents such as web images, pages and other kinds of web multimedia are stored as a web cache. When the documents pass through the web cache system it stores copies of those documents. (An appliance or computer program may be referred to as a web cache system.)
Caching, therefore, helps deliver your website’s information quickly to visitors instead of making them wait for a series of requests that would otherwise slow the user experience.
How Cached Pages are Served
The easiest way to understand the process of caching is to know how a web page is served.
Suppose, for example, you have WordPress caching on your WordPress website.
The first time a visitor accesses the homepage (i.e. the request is processed on the server) the webpage shown is converted into an HTML file and sent to your visitor’s web browser.
Now, as caching is enabled, this HTML file is stored by the server in the extremely fast random access memory (or RAM). So now, when the next time that visitor views the homepage, the server does not need to go through all the process again, it just sends already-prepared HTML file to the browser.
What Does a Web Cache Do?
The temporary storage of web documents like HTML images and pages, a web cache reduces the usage of bandwidth, perceived lag, and server load. Web caching makes it possible for a browser to quickly load the frequently accessed images. The memory cache enhances the speed of screens appearing on a computer.
In the case of phone apps, a cache stores relevant information of the app, and a router can hold onto for quick data access. It would not have been possible for phones, computers, and other devices to have a good speed and performance without a cache.
Although a cache helps in saving time and data, it can bring some problems with as well such as delivering corrupt files, consuming large disk space, and collecting malware. Phones and computers have limited storage space, so all types of cached should take place from time to time.
What Exactly Can be Cached?
For most of the websites, some kind of content gets more easily cached that the others, such as:
- Images, including pictures, logos, etc.
- Other media files
- Style sheets
- Navigation icons
- Downloadable content
These are not changed frequently, so they are cache-friendly and can be cached for a longer time period.
The following items should be cached with extra care:
- Content with authentication cookies
- HTML pages
- Rotating images
However, there are certain items which should not or cannot be cached at all:
- User-specific content
- Content that keeps on changing frequently
- Sensitive data, for example, banking information, login passwords, etc.
Types of Caching
Broadly speaking, web caching occurs in three places:
- Site Caching: Done on the client-side
- Browser Caching: Done on the user (client) side
- Server Caching: Done on the server-side.
Let’s discuss them.
Also known as page or HTTP cache, a site cache temporarily stores data like web pages, web images and other media content when any web page loads for the very first time. Site cache remembers web content, enabling quicker loading every time the web page is visited again. Site caching is completely controlled and taken care of by the end-user.
The website tells a cache for how long the saved data can be stored. A web page with content that does not change frequently can be set for expiring in the future. However, a page that changes often can be set to expire sooner. It ensures the user can see fresh content regularly. The pages that do not change can be loaded quickly from the cache speeding up the process.
Client-side caching is supported by all modern browsers. It is quite efficient because it allows the browser to access the files directly without needing to reload them from the server.
Server caching is similar to site caching except it stores content on a site’s server rather temporarily saving on the client-side. Server caching is fully administered by the server without any involvement of the browser or end-user.
When a user visits your website where the cache is not enabled, then a request is sent by their browser to your server for the page. Your server then must process the request, compiles the document and sends it to the browser. This whole process uses up a lot of server resources and is time—consuming an issue particularly on large sites with greater traffic.
Therefore, the server caching is best for larger websites.
The server stores static snapshots of the requests. So the next time when the same request is made to your server, it scans the cache and, if it finds a stored copy, then it serves the file from there instead of processing every request again. Server caching is set up by you or your web host.
There different types of caching options depending on your requirements:
Mobile caching is web caching for phone devices and mobile applications. The app asks the server for something and records the results in a cache file.
So, next time when the app asks a question to the server, it scans and sees if the server already has the results. If the stored copy is fresh enough, it serves those results from cache. If not, asks the server to deliver new material.
A user cache is a set of temporary cache files for every user who logged. It is useful in case of user-specific content on the website, such as customized membership functionality. It also creates a cache file for visitors who are not logged in so they can’t have access to your specific content.
This caching store compiles PHP code between requests. Every time the PHP script is executed, your server is consulted to see if there are any results present in the cache. If there aren’t any, then the result of the PHP script is stored in the cache. It is saved for users who request the content next and it is loaded if it was already cached.
Microcaching caches static snapshots of content which is generated dynamically for a short period of 1 to 10 seconds. This is considered for sites that receive a very high volume of traffic that features rapidly changing content such as breaking news, sports scores, real-time stock prices, and many more. Microcaching is no benefit for you if your website doesn’t receive enough users in a short timeframe hitting with the same requests.
Edge caching caches the servers to store the content closer to the end-users such as CDN (content delivery network).
Suppose your website is hosted on a server in New York. Also suppose that a user in Sydney, Australia visits the site. Their request will have to travel a very long distance to reach the webserver and travel the same distance back to deliver web pages to the browser. The delay before transferring data begins is called latency. So, with the help of CDN caching, files of a website are cached on various data centers distributed around the world resulting in minimizing the latency. When a user visits your website again from a hundred and thousands of miles away, the site’s file is given to them from a CDN server near to them.
This caching includes storage of database queries so the information is delivered from the cache when required without the need to query the database. Object caching when enabled on your WordPress website, improves the execution time of your PHP, delivers the content faster, and reduces the database loads preventing it from getting overwhelmed.
When your website is requested frequently from different clients, reusing the previously generated requests to speed up the process of new requests is known as WordPress caching. Two things are very important to know in WordPress Caching:
- WordPress Caching Plugins
- Using your host’s build-in cache
Usage of WordPress Caching Plugins
The easiest way to enable caching in your WordPress site is by installing plugins. The caching plugin generates static pages (HTML) of your site and stores it on your server. So, every time a user tries to access your website, your installed caching plugin serves the lighter HTML page than processing the heavier WordPress scripts.
There are several plugins available free as well as paid that can help you enable caching on our websites such as WP Rocket, WP Super Cache, WP Fastest Cache, WP-Optimize, and W3 Total Cache.
One important rule is to never use more than one caching plugin. It won’t make your website any faster but instead could make it a lot slower and break it in the process. A single WordPress caching plugin—properly configured—helps speed up your site. Test, and watch out for unintended display issues, however, since settings on some caching plugins can produce site problems.
Caching Built into Your Host Account
This caching system applies to websites running on the managed WordPress hosting environment. WP Engine, Kinsta, and Flywheel have amazing caching mechanisms making them worthwhile. Caching systems that are used by such hosting companies work at a lower level than the various WordPress Plugins making them more effective. They are specifically tuned to work in a hosting environment which further increases their utility.
For a managed WordPress host, it is advisable to not use a caching plugin. These hosts may not allow the usage of some caching plugins as they are likely to interfere with already implemented caching systems.
Caching is an information technology that helps increase the speed of your website without compromising anything in the process. When used properly and correctly, it results in faster site loading and reduction in the load on your server.
If you are not caching your web pages already, ask someone to help you with WordPress caching.