Hi Ryohei, Thanks for the patch. Here are my two cents.
> I noticed that the COPY performance on PG 17.0 Windows is worse than PG 16.4. > > [...] > > By applying the attached patch to PG 17.0, the copy result is 401.5s. So we are trading a potential 3.8% speedup in certain environments for the increased code complexity due to a couple of added #ifdef's here. If we really want to do this, firstly the patch should have detailed comments in front of #ifdefs so that in 10+ years from now someone who didn't read this thread would know what they are for. Secondly, more detailed research should be made on how this patch affects the performance on Windows depending on the software version and particular choice of hardware. Perhaps what you found is not the only and/or the most important bottleneck. Your patch may (or may not) cause performance degradation in other setups. Last but not least one should double check that this will not cause performance degradation on *nix systems. To be honest, personally I wouldn't bother because of 3.8% speedup at best (for 10+% - maybe). This being said perhaps you and other people on the mailing list (reviewers, committers) feel otherwise. -- Best regards, Aleksander Alekseev
