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How To Create A WordPress Website

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Caching is an important part of making your website display faster for a better visitor experience. Getting it right is also just as important. How to cache, what to cache and how long to cache needs to be carefully considered. With proper caching you can also reduce your web server bandwith usage and server load, especially when your visitors browser caching is used when they are returning to view the same pages.

If caching is not used, then every time some-one visits your website the database is accessed to create each page dynamically which slows down the process considerably. If a page takes more than a few seconds to display then your visitor will most likely go elsewhere.

Caches are static files stored on your web server that Joomla uses directly to generate the web page instead of accessing the database. This makes the web pages not only display faster but with a more consistent response time. These files have a set time period and are re-generated again when the web page is accessed and the cache time has expired. If web page content changes often at short intervals then a short cache time is used, longer for pages that are static or infrequently edited.

Keep all caching off when you are developing a web site else you may need to delete the cache files every time you update the website. 

Global System Caching


Conservative Caching

  • Widely used type of caching implemented by web developers allowing each of the cached files to be used by all website visitors.
  • If the cached page exists and has not yet expired then Joomla will use this to create the page and send to the visitor, else the page will be cached again for future visits.
  • Caches Joomla modules individually such as menus, modules, templates and other system items.
  • Allows individual module caching settings.


Progressive Caching

  • Creates a cached page for each individual visitor. Subsequent visitors will have there own copy of the cached page created.
  • This type of caching makes for a slow initial page load time, but subsequent visits for the same visitor are quicker if that cache has not expired.
  • Used for websites that want to serve individual customized pages to visitors which take time to rebuild, so caching will allow fast page displays on subsequent visits by the same person.
  • Should not be used on large websites because this method will consume a great deal of web server resources.
  • Does not work with individual module caching becasue all modules are combined in a single cache.


cache setting


Module Caching


  • Within each module in Joomla, you can turn the caching to "global" or "off"  for each indivividual module. From the main menu, go to Extensions -> Modules-> {select the module from menu}.
  • Use with conservative caching so that individual module caching settings can work correctly.
  • Each module also has a caching time period.
  • Modules that require dynamic data from cookies or from the database should have "no caching".


module caching


System Page Caching


  • This type of caching creates a seperate folder within Joomla with all the individual pages cached. Everything on each web page is cached, including all modules, components, templates etc.
  • Only works for site visitors and not any logged on site members.
  • Creates faster page load times and is ideal for static pages that are infrequently modified.
  • Very inflexible and will cause issues where dynamic information is required to display a web page that uses cookies or the database.
  • When web page content is edited you will need to delete the pages cache or wait for the cache time to expire before the changes are displayed.
  • Exclude pages for this type of caching using the "Exclude Menu Items" or the "Exclude URL's" in the setting of  the "System Page Cache" plugin which is where you turn Page Caching on or off.
  • Do not use on sites that require logged on users because they will require new active session data.
  • Pages needing cookie data will also not work because they need to set certain options or other functionality dynamically. You can exclude specific pages from being cached if they use cookie data or database information.
  • Optional Browser caching is possible which will then make the page display using the visitors own browser cache file from their own computer if it exists. Do not use this option if your website has sensitive information which could be a security issue if stored on a visitors computer.
  • You can page through your website one by one to generate a cached version of each page. Make a note of the number of files being created and also verify any excluded pages do not generate a cache file.


page cache plugin


You can exclude specific pages from being cached if they use cookie data or database information.


page cache exclusion


Cache Time

Setting the cache time for how long in minutes the cache file is valid should be carefully considered and tested.
If your website has a high volume of traffic and page content is regularly updated then a short cache time should be used, maybe 5 to 10 minutes.
Web pages that are static and visitor traffic is low then much higher cache times would probably be best, possibly a week or a month.


Purging Expired Cache

Old cache files should be regularly deleted so as to save web server space. This is easy enough to do within Joomla.
From the menu go to System -> Clear Cache -> Clear Expired Cache (menu item)-> Clear Expired Cache (button).



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