Comment by PeterisP

For me, an interesting statement was "However, it took 6 days to fetch all data for all 17 million products." - in my experience of DB systems, 17 million entries is significant but not particularly much, it's something that fits in the RAM of a laptop and can be imported/exported/indexed/processed in minutes (if you do batch processing, not a separate transaction per entry), perhaps hours if the architecture is lousy but certainly not days.