How Long Does it Take After You Click on the "Published" Option for Your Published Content to Appear?
We are working to reduce the delay in seeing your edits to published pages by sending a request to Amazon Cloudfront, the caching network we use for the WebCMS, when you publish your page.
On this page:
Short Answers
- New pages or files: newly published content is immediately available on www.epa.gov or espanol.epa.gov after you select Publish Now
- An edited page or replaced file:
- HTML pages you can edit: once you republish, less than 10 seconds
- HTML pages that are generated by the system: up to 30 minutes, with exceptions
- PDF and other files: once you replace the file, up to 10 minutes (see below)
Since the WebCMS is fairly server-intensive, and servers are expensive, we rely upon:
- Amazon CloudFront, a global caching/edge service, to serve our pages and files to the public, and
- Extensive page caching in Drupal
To cache copies of our pages.
There's browser caching as well: Chrome, Edge, and Firefox will save copies of pages and files to make your browsing faster. (Chrome is particularly aggressive about caching.) You can clear the browser cache yourself.
Clearing Chrome Browser Cache
Chrome has an option to help eliminate caching problems.
- Open Developer Tools (press F12 or press ctrl-shift-i).
- Once the Developer Tools box is open, right click on the refresh button located at top of the browser window, to the left of the URL.
- A dropdown will appear and it will give you options to "Empty Cache and Hard Reload."
PDF, Image, and Other Non-HTML Files
For uploaded PDF files, non-HTML files, and images, Amazon CloudFront will cache www.epa.gov files for 10 minutes.
Uploading a PDF
When you upload a PDF file, and you or a reader clicks the link for that PDF file, Amazon CloudFront will first attempt to serve the file out of their cache. If it's not there, CloudFront will come to EPA (AWS S3) and look for the file there. A copy of the file gets saved into CloudFront and is given a timestamp that's dated 10 minutes ahead. This timestamp is called the file's "time to live" or "TTL".
Replacing the PDF File
Now, you want to replace the file. Your updated file will replace the old version at EPA's AWS S3 bucket. A visitor clicks the link for the file. If it's been less than 10 minutes since you or anyone else requested the file, the 10-minute wait isn't yet up, so CloudFront won't actually look for a new version--it will serve the cached copy, which is not your new version. It's only after 10 minutes that CloudFront will check to see if there's a newer version.
CloudFront will check for a newer version in AWS S3 the next time someone requests the file provided the 10 minutes has passed since the last request for that file.