Caching and Refreshing Content

Problem

Content on the site, such as a homepage or a list of upcoming events, isn't updating.

Background Information

There are three systems at play that keep website performance in check.

  1. Drupal's internal index of content is refreshed nightly (in a scheduled maintenance task called "cron"). This index makes dynamic lists possible.
  2. Drupal's internal cache of blocks and theme elements is cleared on a per-page basis after 6 hours, and after certain events.
  3. The website employs a secondary caching layer called Varnish. It caches pages very aggressively, but expires after 6 hours.

Solution

  • If there's a discrepancy between logged-in and unlogged views of the same page, press CTRL-F5 in your unlogged web browser to clear the Varnish cache for that page. Then reload the page normally.
  • If a dynamic list isn't showing new content whether logged-in or not, wait overnight for the cache to clear. For time-critical content, contact ITTS and request a cache clear for your website.