Re: qsort, once again

Greg Stark <gsstark(at)mit(dot)edu> writes:
> My question explicitly recognized that possibility. I'm just a little
> skeptical since the comparison function in Postgres is often not some simple
> bit of tightly optimized C code, but rather a complex locale sensitive
> comparison function or even a bit of SQL expression to evaluate.

Yeah, I'd guess the same way, but OTOH at least a few people have
reported that our qsort code is consistently faster than glibc's (and
that was before this fix). See this thread:
http://archives.postgresql.org/pgsql-hackers/2005-12/msg00610.php

Currently I believe that we only use our qsort on Solaris, not any other
platform, so if you think that glibc's qsort is better then you've
already got your wish. It seems to need more investigation though.
In particular, I'm thinking that the various adjustments we've made
to the sort support code over the past month probably invalidate any
previous testing of the point, and that we ought to go back and redo
those comparisons.

regards, tom lane