Dupe of http://news.ycombinator.com/item?id=4327654 (thanks to non-canonical URL).

This submission's title (taken from the blog post) is more interesting.

Incidentally, this is the same reason why sorting in C++ using std::sort is much faster than qsort[1]. Basically, std::sort, which is templated, lets the compiler do the same specialization and inlining that this article talks about.

[1] http://radiospiel.org/sorting-in-c-3-times-faster-than-c

(Reposting the comment I had left on the other version of this article:)

PostgreSQL should really be using a radix sort for these data types, not a quick sort (however "optimized").