Is it necessary to compact an OrientDB after deletions?

On a Sonatype Nexus repository server which uses an OrientDB instance as a database backend, we observe the database steadily growing despite the repository contents getting regularly deleted. We'd expect the database size to (at least occasionally) shrink and to overall stay at roughly the same size. How does OrientDB handle deletions? Is there a way to check if the database holds outdated information, and is it necessary / possible to regularly "purge" or "compact" an OrientDB?