Remotely inserting 3.5m records mysql
It would be convenient to diagnose where is the performance bottleneck in this case. Can you monitor the network throughput / CPU usage / disk usage to see which one is higher while uploading?


If it's a network bandwidth problem, make sure you're using compression in server/client protocol, any client should have this feature, Mysql Workbench for sure does
Most probably it's not related to the fact that the data comes from Access
Having your own test Mysql server inside your network would be of use for two things: importing the data there to see if the network is the problem; and importing it there and exporting it from there, forcing a multi-row insert export format