Maybe, maybe not.

Without example IN and OUT it's hard to guess what an OP really tried to achieve in messy code... 🤷🏾

That's why I asked for an SSCCE

And ranking columns looks weird.

Anyway, the question how to sort data which doesn't fit into memory is more interesting for me!°

Call it a thread drift, but the monastery is currently not really busy answering interesting questions. ;)

And I learned a lot about sorting ...

°) like https://www.geeksforgeeks.org/external-sorting/