Cache problems 2

In most cases the static cache time solves the problem, what you can see in the Cache problems’ first part. But if there would be still a problem, then it could be, that the SystemGlobal ConfigurationSystemCache is used, and the ExtensionsPlugin ManagerSystem – Cache plugin is turned on too. Sometimes these two doesn’t work well together, so you should use only one of them. You wouldn’t even need both of them anyway, here is an explanation which one does what, and you should choose that one, which fits your needs the best.

Extensions → Plugin Manager → System – Cache

This is looking at the whole code of your website, makes a copy of it, and it will show that until you manually clear the cache in the SystemClear cache.

System → Global Configuration → System → Cache

It’s totally seperate from the other one. This cache is only saving down the modules, but not the content (articles, webshop product pages, etc.). This cache can be cleared in the SystemClear cache, or when the SystemGlobal ConfigurationSystemCache Time has past, it happens automatically. There are two options in it:

1

Conservative caching

This works the way that a visitor comes to a page

  • Joomla checks, if there is a cached version of that page
    • if there is, it will show it
    • if there isn't, or the cache time has past, it will create a new one.
  • Another visitor comes to the same page
    • if the cached page that was created at the other visitor is still available, that will be shown
    • if not, a new one will be created.
2

Progressive caching

This works the way that a visitor comes to a page

  • Joomla checks, if there is a cached version of that page for this visitor
    • if there is, it will show it
    • if there isn't, or the cache time has past, it will create a new one.
  • Another visitor comes
  • Joomla checks, if there is a cached version of that page for this visitor
    • if there is, it will show it
    • if there isn't, or the cache time has past, it will create a new one.

Basically it makes a new cache file for every single visitor, so this progressive caching only makes your website faster, if the same visitor comes to the same page within the lifetime of the cached version of the page. If this doesn’t happen, it is worst than disabling the cache, because the website not only has to load everything, that would load during disabled cache, but it also has to create cache.

Because of the same reason, think about the cache time at the Conservative caching too, if it’s too small, and you don’t have visitors that often, it could have more negative effects, than positive ones.