v13 worked fine with 1M records and with 4.1M. Filesize is 1.4GB.
I was able to open the file(s), select a column, and sort. The sort took a while but not too long, which I expected.
My admittedly very nitpicky observations:
I’d like to preserve the first row if it contains headings.
I’d like to see the Select, Sort commands available as toolbar buttons.
That said, this is really wonderful and helps to solve a big problem for me.
btw, the files I am working with are public data if you need some big files to work with.