Q: Why an import of Datavard transports took such a long time (6-8 hours)?
A: Before performing an upgrade, all services have to be stopped and deactivated, especially Insights collectors, according to the documentation: https://docs.appdynamics.com/display/SAP/Upgrade+or+Uninstall+the+Solution#UpgradeorUninstalltheSolution-UpgradeProcedure