Hi, In <CAEG8a3+BmNeEOLmApOCyktYbiZW=s95dvpod_fxjs+3ievz...@mail.gmail.com> "Re: Make COPY format extendable: Extract COPY TO format implementations" on Thu, 28 Nov 2024 19:02:57 +0800, Junwang Zhao <zhjw...@gmail.com> wrote:
>> > I tested 3 branches: >> > >> > 1. the master branch >> > 2. all v26 patch sets applied >> > 3. Emitting JSON to file using COPY TO v13 patch set[1], this add some >> > if branch in CopyOneRowTo, so I was expecting this slower than master >> > >> > You can see the detailed results here[2], I can not upload files so I >> > just shared the google doc link, ping me if you can not open the link. >> > >> > [1]: >> > https://www.postgresql.org/message-id/CACJufxH8J0uD-inukxAmd3TVwt-b-y7d7hLGSBdEdLXFGJLyDA%40mail.gmail.com >> > [2]: >> > https://docs.google.com/spreadsheets/d/1wJPXZF4LHe34X9IU1pLG7rI9sCkSy2dEkdj7w7avTqM/edit?usp=sharing >> >> Thanks for sharing your numbers. >> >> 1. and 2. shows that there is at least no significant >> performance regression. > > Agreed. Can we focus on only 1. and 2. in this thread? >> I see the patch set of 3. and I think that the result >> (there is no performance difference between 1. and 3.) isn't >> strange. The patch set adds some if branches but they aren't >> used with "text" format at least in per row process. > > It is not used in "text" format, but it adds some assembly code > to the CopyOneRowTo function, so this will have some impact > on the cpu i cache I guess. > > There is difference between 1 and 3, 3 is always better than 1 > upto 4% improvement Can we discuss 1. and 3. in the [1] thread? (Anyway, we may want to confirm whether these numbers are reproducible or not as the first step.) > I forgot to mention that the comparisons > are in *sheet2*. Thanks. I missed it. Thanks, -- kou
