It would be interesting to know what you mean by naive in this context?
I mean the algorithm as you will learn it from the usual "introduction to algorithms and data structures" course, without taking in consideration practical issues like having a hierarchical memory with several levels of cache or that data is frequently not completely random.
I think that you may be missing the point
Well, actually I didn't want to make any point besides showing my surprise for the suboptimal algorithm used in that particular implementation of the sort command.
I had always taken for granted, that nothing could be faster than the external command (at least, for big data sets where the required set up overhead gets diluted) but now, I would also check with other approaches as for instance the excellent Sort::External.
