Clearing Caches for Drupal and WordPress

Learn how to clear cache for Drupal and WordPress sites on Pantheon's Global CDN.

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Pantheon extends the core functionality of caching mechanisms within WordPress and Drupal so that caches are cleared within the site's frame and from our Global CDN service.

Granular Cache Clearing

Use the Pantheon Advanced Page Cache plugin or module to automatically clear caches for related pages as content is updated. No configuration needed, simply install and enable to take advantage of the granular cache clearing capabilities of the Global CDN.

Lower-level documentation for custom implementation of caching strategies is also coming soon. Please contact our enablement team if you are interested in implementing a custom cache strategy.

Full Cache Clearing

We refer to this as "full cache clearing" because the operation removes all pages from cache at once. There are three methods you can use to clear all caches for a given environment of a site:

  • Pantheon Dashboard
  • Site Admin
  • Command Line

Note: To clear the Redis cache, please see our Redis doc.

Pantheon Dashboard

  1. Navigate to the Site Dashboard and select the desired environment.

  2. Click the Clear Caches button:

    Clear Cache Button

Site Admin

  1. Navigate to the Site Dashboard and select the desired environment.

  2. Click the Visit Site button and login.

  3. Navigate to Settings > Pantheon Page Cache, then click Clear Cache:

    WordPress Clear Caches

  1. Navigate to the Site Dashboard and select the desired environment.

  2. Click the Visit Site button and login.

  3. Navigate to Configuration > Development > Performance, then click Clear all caches:

    Drupal 8 Clear Caches

  1. Navigate to the Site Dashboard and select the desired environment.

  2. Click the Visit Site button and login.

  3. Ensure the Pantheon Platform API module is enabled:

    Pantheon Platform API module

  4. Navigate to Configuration > Development > Performance, then click Clear all caches:

    Drupal 7 Clear Caches

Command Line

If you're working from a terminal prompt or looking to automate parts of your workflow, use Terminus to clear caches from the command line:

terminus env:clear-cache site.env

Replace site and env with your site name and the correct environment.

Troubleshooting

Clear Cache Fails in Dashboard or Terminus

If you see a notification on the Dashboard indicating a failure to clear cache, this is usually due to a PHP error, redirect, or other code-related issue. While the Dashboard notification may not help much to debug, running the same command via Terminus will likely provide actionable information.

Some good troubleshooting first steps include:

  • Commenting out redirections in settings.php, wp-config.php, or elsewhere.

  • Resolve any fatal PHP errors.

  • Isolate which plugin or module may be causing the issue by turning them all off, then turning on one by one.

  • Check if the issue is theme related by using an unmodified default theme like Bartik or Twenty Nineteen.

Cache Is Cleared from Dashboard and Application but New Changes Are Not Visible

This usually happens when using a 3rd Party CDN on top of Pantheon like Cloudflare, Stackpath, etc. Try clearing the cache from the 3rd-party CDN's dashboard.