The current implementation of the Keycloak ingester reads and applies the 'full' mutation which replaced everything in the catalog, regardless of if the users and groups have been changed.

To improve efficiency, the 'delta' mutation option can be used to update only the users and groups that have changed since the last sync. Refer to how this is done by the GitHub org ingester. 

This change requires some investigation on the actual performance impact of the full mutation and whether or not this enhancement would be worth the effort as it may require rewriting parts of the ingester.