Re: POC: converting Lists into arrays

On Sun, 24 Feb 2019 at 15:24, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> I haven't attempted any performance measurements on this, but at
> least in principle it should speed things up a bit, especially
> for complex test cases involving longer Lists. I don't have any
> very suitable test cases at hand, anyway.

I've not yet looked at the code, but I thought I'd give this a quick benchmark.

Using the attached patch (as text file so as not to upset the CFbot),
which basically just measures and logs the time taken to run
pg_plan_query. Using this, I ran make installcheck 3 times unpatched
and same again with the patch. I pulled the results of each run into a
spreadsheet and took the average of each of the 3 runs then took the
sum of the total average planning time over the 20334 individual
results.

Results patched atop of 067786cea:

Total average time unpatched: 0.739808667 seconds
Total average time patched: 0.748144333 seconds.

Surprisingly it took 1.13% longer. I did these tests on an AWS
md5.large instance.

If required, I can send the entire spreadsheet. It's about 750 KB.

--
David Rowley http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services