25 years ago my company Needed to match lists against a collection numbers not to call. Probably ran lists of 20k daily or more. So I wrote up a simple python program to match against a special format txt file. A few seconds for big lists at most.

Higher up IT people were horrified, and commissioned a proper oracle soliton. It ran around a 1-2 records per second. So all day for a typical list. They were quite proud of this. I think they spent 25-50 grand on IBM support to get it setup.

They were not happy when we said we would only consider using it if they could speed it up 5000 times faster.

We never heard back.