RavenDB has the notion of HTTP caching out of the box, what this means is that by default, without you having to take any action, RavenDB will cache as much as possible for you. It can get away with doing this because it is utilizing the notion of the 304 Not Modified response. The second time that we load an entity or execute a query, we can simply ask the server whatever the data has been modified since the last time we saw it, and if it wasn’t, we can just skip executing the code and get the data directly from the cache.

This saves a lot in terms of bandwidth and processing power, it also means that we don’t have to worry about RavenDB’s caching returning any stale results, because we checked for that. It does mean, however, that we have to send a request to the server. There are situation where we want to squeeze even better performance from the system, and we can move to RavenDB’s aggressive caching mode.

Aggressive caching means that RavenDB won’t even ask the server whatever anything has changed, it will simply return the reply directly from the local cache if it is there. This means that you might get stale data, but it also means that you’ll get it fast.

You can activate this mode using:

using (session.Advanced.DocumentStore.AggressivelyCacheFor(TimeSpan.FromMinutes(5)))
{
    session.Load<User>("users/1");
}

Now, if there is a value in the cache for users/1 that is at most 5 minutes old, we can directly use that.

It also works on queries too:

using (session.Advanced.DocumentStore.AggressivelyCacheFor(TimeSpan.FromMinutes(5)))
{
    session.Query<User>().ToList();
}

This is an explicit step beyond the normal caching, and it does mean that you might get out of date information, but if you really want to reduce the number of remote calls, it is a really nice feature.