On Sat, Oct 1, 2022 at 12:14 PM Tom Lane <t...@sss.pgh.pa.us> wrote: > I spent some time today looking into the question of what our qsort > code actually does. I wrote a quick-n-dirty little test module > (attached) to measure the number of comparisons qsort really uses > for assorted sample inputs.
Reminds me of the other sort testing program that you wrote when the B&M code first went in: https://www.postgresql.org/message-id/18732.1142967...@sss.pgh.pa.us This was notable for recreating the tests from the original B&M paper. The paper uses various types of test inputs with characteristics that were challenging to the implementation and worth specifically getting right. For example, "saw tooth" input. -- Peter Geoghegan
