If it only took 59 minutes to process millions of records, it was nowhere near as bad as it could have been. At around one millisecond per record, it sounds like you probably don’t even have any accidental quadratic time complexity on the number of records! What are you complaining about?

I know a phone company where just the cronjob that sends bills took over 3 days to run. I guess it's not a problem until it takes more than a month.