A set of features is identified in a resource provided from a Content Delivery Network (CDN), a feature causing a first information available in the resource at a first time to change to a second information in the resource at a second time responsive to an event. A set of weights is determined corresponding to the set of features. A weight is related to a corresponding feature in the set of features. Using the set of weights and the set of features to compute an entropy comprising a probability that the resource is going to change. Using the entropy, a stale probability is computed, comprising a probability that an outdated version of the resource is going to be served from a cache in the CDN at the second time. A refresh information is adjusted responsive to the stale probability exceeding a threshold probability.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A method for predictive adjustment of resource refresh in a Content Delivery Network (CDN), the method comprising: identifying a set of features in a resource, the resource being provided from the CDN, a feature in the set of features causing a first information available in the resource at a first time to change to a second information in the resource at a second time responsive to an event; determining a set of weights corresponding to the set of features, wherein a weight in the set of weight is related to a corresponding feature in the set of features; computing, using the set of weights and the set of features, an entropy, the entropy comprising a probability that the resource is going to change; computing, using the entropy, a stale probability, the stale probability comprising a probability that an outdated version of the resource is going to be served from a cache in the CDN at the second time; and adjusting a refresh information responsive to the stale probability exceeding a threshold probability, wherein adjusting the refresh information changes at least one of the entropy and an other component used in computing the stale probability. 2. The method of claim 1, further comprising: computing a cache probability, the cache probability comprising a probability that the resource is provided from the cache in the CDN, the other component comprising the cache probability; and using the cache probability in computing the stale probability, wherein the adjusting the refresh information changes the cache probability. 3. The method of claim 1, further comprising: computing a tier probability, the tier probability comprising a probability that the cache exists in a particular tier in the CDN, the other component comprising the tier probability; and using the tier probability in computing the stale probability, wherein the adjusting the refresh information changes the tier probability. 4. The method of claim 1, the refresh information comprises: information configured to refresh the resource responsive to the event. 5. The method of claim 1, the refresh information comprises: information configured to refresh the cache responsive to the event. 6. The method of claim 1, the refresh information comprises: information configured to refresh a tier of caches in the CDN responsive to the event, the tier including the cache. 7. The method of claim 1, the refresh information comprises: information configured to refresh one of (i) the resource, (ii) the cache, and (iii) a tier of caches in the CDN, upon elapse of a period. 8. The method of claim 1, wherein the outdated version is a first version of the resource, wherein the resource has been updated to a second version by a source of the resource in a repository accessible from the CDN before the second time. 9. The method of claim 1, wherein the identifying, the computing using the set of weights and the set of features the entropy, the computing using the entropy the stale probability, are each performed relative to a portion of the resource, the portion comprising a page of the resource. 10. The method of claim 1, wherein the resource is a content. 11. The method of claim 1, wherein the method is embodied in a computer program product comprising one or more computer-readable tangible storage devices and computer-readable program instructions which are stored on the one or more computer-readable tangible storage devices and executed by one or more processors. 12. The method of claim 1, wherein the method is embodied in a computer system comprising one or more processors, one or more computer-readable memories, one or more computer-readable tangible storage devices and program instructions which are stored on the one or more computer-readable tangible storage devices for execution by the one or more processors via the one or more memories and executed by the one or more processors. 13. A computer program product for predictive adjustment of resource refresh in a Content Delivery Network (CDN), the computer program product comprising: one or more computer-readable tangible storage devices; program instructions, stored on at least one of the one or more storage devices, to identify a set of features in a resource, the resource being provided from the CDN, a feature in the set of features causing a first information available in the resource at a first time to change to a second information in the resource at a second time responsive to an event; program instructions, stored on at least one of the one or more storage devices, to determine a set of weights corresponding to the set of features, wherein a weight in the set of weight is related to a corresponding feature in the set of features; program instructions, stored on at least one of the one or more storage devices, to compute, using the set of weights and the set of features, an entropy, the entropy comprising a probability that the resource is going to change; program instructions, stored on at least one of the one or more storage devices, to compute, using the entropy, a stale probability, the stale probability comprising a probability that an outdated version of the resource is going to be served from a cache in the CDN at the second time; and program instructions, stored on at least one of the one or more storage devices, to adjust a refresh information responsive to the stale probability exceeding a threshold probability, wherein adjusting the refresh information changes at least one of the entropy and an other component used in computing the stale probability. 14. The computer program product of claim 13, further comprising: program instructions, stored on at least one of the one or more storage devices, to compute a cache probability, the cache probability comprising a probability that the resource is provided from the cache in the CDN, the other component comprising the cache probability; and program instructions, stored on at least one of the one or more storage devices, to use the cache probability in computing the stale probability, wherein the adjusting the refresh information changes the cache probability. 15. The computer program product of claim 13, further comprising: program instructions, stored on at least one of the one or more storage devices, to compute a tier probability, the tier probability comprising a probability that the cache exists in a particular tier in the CDN, the other component comprising the tier probability; and program instructions, stored on at least one of the one or more storage devices, to use the tier probability in computing the stale probability, wherein the adjusting the refresh information changes the tier probability. 16. The computer program product of claim 13, the refresh information comprises: information configured to refresh the resource responsive to the event. 17. The computer program product of claim 13, the refresh information comprises: information configured to refresh the cache responsive to the event. 18. The computer program product of claim 13, the refresh information comprises: information configured to refresh a tier of caches in the CDN responsive to the event, the tier including the cache. 19. The computer program product of claim 13, the refresh information comprises: information configured to refresh one of (i) the resource, (ii) the cache, and (iii) a tier of caches in the CDN, upon elapse of a period. 20. A computer system for predictive adjustment of resource refresh in a Content Delivery Network (CDN), the computer system comprising: one or more processors, one or more computer-readable memories and one or more computer-readable tangible storage devices; program instructions, stored on at least one of the one or more storage devices for execution by at least one of the one or more processors via at least one of the one or more memories, to identify a set of features in a resource, the resource being provided from the CDN, a feature in the set of features causing a first information available in the resource at a first time to change to a second information in the resource at a second time responsive to an event; program instructions, stored on at least one of the one or more storage devices for execution by at least one of the one or more processors via at least one of the one or more memories, to determine a set of weights corresponding to the set of features, wherein a weight in the set of weight is related to a corresponding feature in the set of features; program instructions, stored on at least one of the one or more storage devices for execution by at least one of the one or more processors via at least one of the one or more memories, to compute, using the set of weights and the set of features, an entropy, the entropy comprising a probability that the resource is going to change; program instructions, stored on at least one of the one or more storage devices for execution by at least one of the one or more processors via at least one of the one or more memories, to compute, using the entropy, a stale probability, the stale probability comprising a probability that an outdated version of the resource is going to be served from a cache in the CDN at the second time; and program instructions, stored on at least one of the one or more storage devices for execution by at least one of the one or more processors via at least one of the one or more memories, to adjust a refresh information responsive to the stale probability exceeding a threshold probability, wherein adjusting the refresh information changes at least one of the entropy and an other component used in computing the stale probability.