nandu nandu - 24 days ago 10
Apache Configuration Question

Disadvantages and limitations of ETags

ETags
, as I read about, is one of the ways to implement the
Caching validation
. We are planning to implement this on our servers. We have 2 apaches running. I wanted to know if there are any limitations and disadvantages in using
ETags
. If there are no such limitation, then why ain't it being used as a simple rule in configuring one's server(s)?.

Answer

Using cache validation means that the request will make a network call and hit the application, regardless. The application must take care of the ETag and decide if the former response is still valid or not. This, effectively, means that your application will build the whole response again just to calculate the ETag. This means that ETags will save you some bandwidth if your responses are heavy, but may not save you too much otherwise. If your responses are heavy, usually the first response is to gzip.