Overview

To ensure that users can obtain the latest content with minimal delay in different scenarios, eSurfing Cloud CDN provides the purge and the prefetching feature.

Feature Overview

The purge and prefetching module provides features for purging content, prefetching content, and viewing content purge or prefetching tasks. The following table describes the features.

Feature	Description
Purge	eSurfing Cloud CDN supports the following methods of purging: URL-based purge, directory-based purge, and regex-based purge. These methods have different implementation mechanisms while they ensure that users can access the latest content. The purge feature is often used to remove stale contents on CDN nodes after the contents on origin servers are updated.
Prefetching	If you submit a prefetching task, CDN POPs are automatically triggered to fetch the latest content from your origin server and then store in cache. After the prefetching task is complete, the latest content is cached on the CDN POPs. In this case, if a client requests the content from a CDN POP, the CDN POP returns the cached content to the client. This feature is often used to trigger CDN POPs to prefetch content before the release of popular files and major promotion activities. This feature can help reduce workloads on your origin server and increase the CDN cache hit ratio, thus improve access experience of the first users after you release a popular file.
Viewing purge and prefetching Tasks	You can set custom conditions to query the execution status of purge or prefetching tasks.

Content Delivery Network

Purge and prefetching overview