IIRC copy_expert just lets you enter the postgres COPY command that's used to start the transfer manually, which by itself doesn't change anything. It does all

IIRC copy_expert just lets you enter the postgres COPY command that's used to start the transfer manually, which by itself doesn't change anything. It does allow you to use the BINARY transfer format, though, and that's quite often the fastest version, at the cost of a more complicated data transformation step.