Hello @Anonymous
Are the rest tables having similar amount of data?
If you are using a Self-Hosted Integration Runtime then there are some factors which can slow the Copy performance, Viz.: Network Bandwidth at IR VM, number of Nodes configured in SHIR, RAM configuration for SHIR
When using self-hosted IR, you can take either of the following approaches:
a) Manually scale up the machine.
b) Scale out to multiple machines (up to 4 nodes), and a single copy activity will partition its file set across all nodes.