Re: Why percent_rank is so slower than rank?

Tom Lane <tgl@sss.pgh.pa.us> wrote:
> I'm not sure whether or not to back-patch this into 9.0 and 8.4. 
> The code in tuplestore.c hasn't changed at all since 8.4, so
> there's not much risk of cross-version bugs, but if I did miss
> anything we could be shipping a buggy version next week. 
> Thoughts?
Is there a performance regression involved, or is it a new feature
which hasn't performed well on this type of query until your patch? 
If the latter, I'd be inclined to give it some time on HEAD and
release it in the *following* minor release unless you're *very*
confident it couldn't break anything.
It's an uphill battle to convince managers that it's safe to apply
minor upgrades with minimal testing.  It doesn't take to many slips
for the boulder to roll all the way back to the bottom of that hill.
-Kevin