The first time bloom connects to a Neo4j database, a lot of work has to be done at the backend.
When Bloom connects to a database, it will try to fetch extensive metadata of the Neo4j database. So when Bloom gets all the metadata, it will decide which indexes will be used for matching and searching. It will also figure out which labels do not have many nodes and those nodes' properties can be searched even when those properties do not have indexes. Bloom is also getting information about the user permissions (write or read-only user) and the capabilities of the DB looking through the store procedures (is GDS installed? is Bloom Plugin installed?) Bloom will try to do metadata fetching from the remote database before you start to use Bloom to do research.
If you have additional questions or if Bloom takes an excessively long time to load please don't hesitate to open a support ticket by emailing email@example.com.