clear cache differneces?

clear cache differneces?

2 posts / 0 new
Last post's picture
Points: 0
clear cache differneces?

What's the difference between the three different clear cache options and when is each option best used?

Acquia Cloud - "Clear Varnish Cache"
Drupal - admin/config/development/performance "clear all caches"
Terminal - $ drush @sitename cc

Thank you in advance for any help - this is new to me and quite confusing.

Resolved (feature request)
dmyburgh's picture
Points: 99

Varnish cache sits in front of your website and caches the final output of the site and then shows it to anonymous users. So you could change things on your site, but not have them appear immediately for anonymous users.

The other two caches are the same. These are Drupal's internal caches. They can be separate into things like css-js, block, menu, etc. So if you change any of those things in your site, you will often have to clear them (or "cc all") before they're visible to other users. These caches must be cleared first, before clearing Varnish caches.

So here's an example workflow:

  • Edit the content of a block and save it
  • If block caching is turned on, you likely won't see the changes even as an authenticated user
  • Clear Drupal caches (performance page or drush cc)
  • You now see the changes as authenticate user
  • Anonymous user may not see the block content changes yet
  • Clear Varnish caches
  • All users see the new block content.
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