The embodiments herein describe a CDN that uses revalidation to force edge servers to refresh their cached objects (i.e., download new copies of the objects from the origin data center). Revalidation can be used by edge servers to determine whether an object currently cached at the edge servers has been updated or changed in the origin data center. The embodiments herein leverage revalidation to perform a forced refresh to force the edge servers to refresh their cached object, regardless whether those cached objects match the objects stored in the origin data center. A forced refresh can be used when there is a network connection that may have caused the cached objects to become corrupted. Moreover, the forced refresh can be performed in batches so as not to overwhelm the network and computing resources in the CDN.
BACKGROUND (1) A content delivery network, or content distribution network (CDN), is a geographically distributed network of edge servers and their origin data centers. Their goal is to provide high availability and performance by distributing the service spatially relative to end users. CDNs came into existence to mitigate performance bottlenecks as the Internet was becoming a mission-critical medium for people and enterprises. Since then, CDNs have grown to serve a large portion of the Internet content today, including web objects (text, graphics and scripts), downloadable objects (media files, software, documents), applications (e-commerce, portals), live streaming media, on-demand streaming media, and social media sites.
1. A method, comprising: receiving, at an origin data center, requests from edge servers to determine whether tags for copies of a first plurality of media objects stored at the edge servers match corresponding tags for copies of the first plurality of media objects stored at the origin data center; upon determining the tags at the edge servers do not match the tags at the origin data center, performing a forced refresh of the copies of the first plurality of media objects in a content delivery network (CDN) stored at the edge servers in the CDN with the copies of the first plurality of media objects stored at the origin data center; and upon determining the first plurality of media objects have been refreshed, performing a forced refresh on a second plurality of media objects in the CDN. ||
8. A system, comprising: a processor; memory comprising computer program code that, when executed by operation of one or more computer processors, performs an operation comprising: performing a forced refresh of a first plurality of media objects in a content delivery network (CDN) as part of a revalidation process associated with edge servers in the CDN, wherein the revalidation process determines whether the first plurality of media objects at the edge servers matches copies of the first plurality of media objects at an origin data center; subdividing tags corresponding to media objects in the CDN to form a plurality of batches, wherein the first plurality of media objects is in a first batch and a second plurality of media objects is in a second batch; and upon determining the first plurality of media objects have been refreshed, performing a forced refresh on the second plurality of media objects in the CDN. ||
14. A method, comprising: subdividing media objects cached at edge servers in a content delivery network (CDN) to form a plurality of batches; receiving, at an origin data center, requests from the edge servers to determine whether tags for copies of the media objects cached at the edge servers match corresponding tags for copies of the media objects cached at the origin data center; and upon determining the tags at the edge servers do not match the tags at the origin data center, performing a forced refresh of the copies of the media objects cached at the edge servers in the CDN with the copies of the media objects cached at the origin data center, wherein the forced refresh is performed on each of the plurality of batches at different times.