Refresh cached content early, before its time to live expires, so end users will not have to wait for a response from the origin.
If a client requests an object after the asynchronous refresh begins—but before the time to live expires—the Edge Server will continue to serve the older object to the client until its time to live expires or the Edge Server receives the refreshed object from the origin.
To use Cache Prefreshing:
Set the slider to the percentage of an object’s time-to-live (TTL) after which you would like the Akamai edge server will asynchronously refresh the object in cache.
If, for example, an object has 10 minutes to live, and a response from the origin takes 30 seconds, the optimal setting would be 95% or lower of the object’s time to live.
This way, the object is refreshed in enough time that end users will receive that object without having to wait for the response from the origin, but not so early that it will increase load on the origin.
Be aware that the percentage you choose depends on:
- The frequency of end user requests – Setting too high a percentage and having too few requests could mean the object expires and an end user must wait for the response from the origin.
- The length of time for the origin to send the whole response – if the origin has not finished sending the new object by the time the original object expires, then users will have to wait for the origin to respond.