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Admin
Forum Admin
Australia
41 Posts |
 Posted - 04/12/2023
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For anyone editing or customising a web site, caching can be a huge problem.
What is Caching?
Caching is the practice of retaining data so that the same data no longer needs to be retrieved from the web. Content such as images, JavaScript and CSS style sheets can be common to all pages on a web site, so being able to use that data from a previous download of a page not only makes the page itself load faster but it reduces the user's data usage.
What is the data usage for downloading a web page?
Web pages are comprised of text, images, scripts and style sheets that make up the web page and governs their look and feel. Today may websites are using content management system (CMS) software like WordPress because it enables site owners to create nice looking web sites with little to know experience in web page design. Unfortunately
CMS cater for all scenarios and load a swag of scripts and style sheets even though the page in question might not be using them. Consequently downloading a web page the first time can be more than 1 MB download. But caching can reduce that download dramatically by using the data already downloaded and stored in cache.
Who caches and where is the data stored?
Where the cached data is stored depends on who is doing the caching:
- Your Web Browser
- The Web Site
- The Web Server
- The Host's Data Centre
- Your Internet Service Provider
Caching by your web browser
Web browsers are designed to cache to speed up your web experience. Browser settings can govern how long data is retained and the user can "clear cache" at any time.
Web site caching
CMS like WordPress can use caching plugins and services in the hope of decreasing download times to enhance their page ranking with search engines. Cached pages are stored within the website. The only real saving is on processor time in assembling the page. To clear a site cache the site owner needs to login to their CMS control panel to request the action.
Web server caching
Web servers can cache pages for all websites website in the hope of reducing server load by reducing the time that it takes to process the CMS scripts that assemble the web page. Clearing a web server's cache may require shutting down and restarting the web server. In most cases web servers refresh their cache periodically, for example, in the early hours of the morning when traffic may be low.
Data centre caching
Data in and out of a data centre costs money and data centres try to minimise those costs wherever they can. Consequently they may even go to the length of running a bank of caching servers for the purpose of speeding up their service and reducing the load on the hosting servers.
Internet service (ISP) caching
All ISPs cache data. How much data they cache and how long it is retained depends on how miserly they are. If you are on an unlimited data plan, be prepared to get your data cached for very long periods.
*** As you may now realise, your control over how long data is retained in cache is indeterminable and you have very little control over it. So if you are web developer hoping to see a refreshed result of your latest changes to a web page, good luck!
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How Is Caching A problem?
