When upgrading Orient DB server from 3.0 to 3.2, the server won't start after running ./server.sh due the following error:

com.orientechnologies.orient.core.exception.OCommandExecutionException: Cannot create user guest: role guest does not exist
        DB name="OSystem"
        at com.orientechnologies.orient.core.sql.parser.OCreateSystemUserStatement.lambda$executeSimple$0(OCreateSystemUserStatement.java:99)
        at com.orientechnologies.orient.core.db.OSystemDatabase.executeWithDB(OSystemDatabase.java:197)
        at com.orientechnologies.orient.core.sql.parser.OCreateSystemUserStatement.executeSimple(OCreateSystemUserStatement.java:48)
        at com.orientechnologies.orient.core.sql.executor.OSingleOpServerExecutionPlan.executeInternal(OSingleOpServerExecutionPlan.java:65)
        at com.orientechnologies.orient.core.sql.parser.OSimpleExecServerStatement.execute(OSimpleExecServerStatement.java:49)
        at com.orientechnologies.orient.core.sql.parser.OServerStatement.execute(OServerStatement.java:72)
        at com.orientechnologies.orient.core.db.OrientDBEmbedded.executeServerStatement(OrientDBEmbedded.java:1255)
        at com.orientechnologies.orient.core.db.OrientDB.execute(OrientDB.java:364)
        at com.orientechnologies.orient.server.OServer.createDefaultServerUsers(OServer.java:1058)
        at com.orientechnologies.orient.server.OServer.loadUsers(OServer.java:904)
        at com.orientechnologies.orient.server.OServer.activate(OServer.java:478)
        at com.orientechnologies.orient.server.OServerMain$1.run(OServerMain.java:49)

Orient DB config file orientdb-server-config.xml has the following users added:

Presumably, a guest role needs to be created for the server to start. However, how does one create this role when the server cannot be started?

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 Is there a way to check if the database holds outdated information, and is it necessary / possible to regularly "purge" or "compact" an OrientDB?

Are ArcadeDB & OrientDB both scalable horizontally & vertically?

Kia Ora, I have a program that very frequently requires finding the fastest path (both the node sequence and total cost/length) on graphs containing ~50k nodes. Per run, I require on the order of millions of shortest path requests. I have just finished an OrientDB implementation which has significantly improved the compute time over my initial, non-graphDB attempt (which simply crashed). To perform testing, I am running the server locally on a series of distributed machines. However, in theory, would Neo4J, or another such platform, be faster again? What gains could I expect to receive? Could I host this process online, for example? Ngā mihi.