When using a content distribution network (CDN) such as Amazon CloudFront, you store frequently used data in an edge location near to the user for fast performance. Often, you set up TTL in CDN for your data, which means the edge location will not query back to the server for updated data until TTL expires. You may have situations where you need to update CDN cached content immediately, for example, if you need to correct the wrong product description.

In such a situation, you can't wait for the file's TTL to expire. The rename distribution pattern helps you to update the cache as soon as new changes are published so that the user can get updated information immediately. The following diagram shows the rename distribution pattern:

As shown in the preceding diagram, using the rename distribution pattern with the cache distribution pattern helps to solve the update issue. With this pattern, instead of overwriting the file in the origin server and waiting for the TTL in CloudFront to expire, the server uploads the updated file with a new filename and then updates the web page with the new URL. When the user requests original content, CloudFront has to fetch it from the origin and can't serve the obsolete file that's already cached.

You may not always want to use a CDN; instead, you can use the proxy cache server. Let's learn more about it in the next section.