I feel the need, the need for speed

The site navigation is built up from a hierarchy of data stored in a relational database.

Every user is presented with the same navigation, based on their group memberships.

The navigation hierarchy is updated relatively infrequently.

This sounds like a classic candidate for data caching.

The implementation should result in:
- fewer trips to the database
- less short-lived objects
- less duplicate objects

Which all lead to faster performance.