Based on the volume of data, I think it may take some more time. If there are no network issues, then I would suggest to let it run for some more time, as the data has to be fetched from the database, and the load on your database would also be a factor here.
Number of joins is always a factor. If you have more, expect delays.
Thanks for your reply. You might be right, but the thing is, I can see the progress up till 506,000 rows. The message keeps changing, number of rows increases. But after 506,000 as in the screenshot, I am not able to see any progress at all, even after waiting for 45 minutes. That's what concerns me.