Re: [PATCH] Use optimized single-datum tuplesort in ExecSort

> I've now pushed that bug fix so it's fine to remove the change to
> tuplesort.c now.

Thanks, I've rebased the patch, please find attached the v6.

> 
> I also did a round of benchmarking on this patch using the attached
> script. Anyone wanting to run it will need to run make installcheck
> first to create the required tables.

I've run your benchmark, keeping the best of three runs each time.
This is an intel laptop, so as many things are running on it there is a lot of 
noise... 

Both standard and patched run come from a compilation with gcc -O2. No changes 
have been done to the default settings.

Query #	Master	Patched	Variation
1	884	1627	184.05%
2	364	375	103.02%
3	568	783	137.85%
4	296	297	100.34%
5	421	484	114.96%
6	359	408	113.65%
7	237	251	105.91%
8	806	1271	157.69%

Since I didn't reproduce your slowdown at all on the first run, I tried to 
rerun the benchmark several times and for the "dubious cases" (2, 4 and 7), 
the results are too jittery to conclude one way or another in my case.  I 
don't have access to proper hardware, so not sure if that would be useful in 
any way to just run the bench for thousands of xacts instead. I would be 
surprised the check adds that much to the whole execution though.

I attach a graph similar to yours for reference.


-- 
Ronan Dunklau