Hi Iczer,
Yes, unfortunately, migrating stats (depending on how many stats you have) is often the longest part of the DB migration. That’s why we had to add the option to NOT migrate stats. The difference is huge: in one situation, when I migrated a large number of stats, it took over 20 hours, while when I migrated the same inventory without stats, it took about 15 minutes. To be fair, this is also a function of the CPU speed of the appliance, the network bandwidth between the source VC and the destination VC, and the disk IO bandwidth/latency on either side.
I’m very sorry for this inconvenience.