We've integrated BI Publisher with EM12c. I've developed a report which checks a given database extents information (initial, next, maxextents) at tablespace level. The dataset is chosen as EM repository. The report runs absolutely fine until new data is added to a database. For eg, I created a new tablespace. The new tablespace related info is not getting refreshed despite the fact that I've refreshed the data source and checked that the tablespace exists in the database.
Has the data in the EM repository view been refreshed? The report retrieves data via the published repository views. If the view does not display the latest information, then you will have to wait till the relevant config or monitoring collections are complete.
configuration collections typically happen every 24 hrs, unless you manually trigger them. Thus, your report will show the latest information as soon as the configuration collections complete and the data is refreshed in the EM repository.
You can't make it real time, but here are two examples (Host and Oracle Home) for doing a manual refresh in bulk or on a per target basis: