Re: Performance of ORDER BY

"Steinar H. Gunderson" <sgunderson(at)bigfoot(dot)com> writes:
> By the way, is the new sorting code any better for platforms that already
> have a decent qsort() (like Linux)?

It seemed better to us. Linux' qsort() is really mergesort, which is
better sometimes but often worse --- mergesort tends to have a less
CPU-cache-friendly memory access distribution. Another big problem with
the Linux version is that it pays no attention to sort_mem, but will
enthusiastically allocate lots of additional memory, thereby blowing
whatever cross-backend memory budgeting you might have been doing.

If you care there is quite a lot of discussion in the -hackers and
-performance archives from last spring or so.

regards, tom lane