Re: Make COPY format extendable: Extract COPY TO format implementations

On 2024-01-24 We 03:11, Michael Paquier wrote:
> On Wed, Jan 24, 2024 at 02:49:36PM +0900, Sutou Kouhei wrote:
>> For COPY TO:
>>
>> 0001: This adds CopyToRoutine and use it for text/csv/binary
>> formats. No implementation change. This just move codes.
> 10M without this change:
>
> format,elapsed time (ms)
> text,1090.763
> csv,1136.103
> binary,1137.141
>
> 10M with this change:
>
> format,elapsed time (ms)
> text,1082.654
> csv,1196.991
> binary,1069.697
>
> These numbers point out that binary is faster by 6%, csv is slower by
> 5%, while text stays around what looks like noise range. That's not
> negligible. Are these numbers reproducible? If they are, that could
> be a problem for anybody doing bulk-loading of large data sets. I am
> not sure to understand where the improvement for binary comes from by
> reading the patch, but perhaps perf would tell more for each format?
> The loss with csv could be blamed on the extra manipulations of the
> function pointers, likely.

I don't think that's at all acceptable.

We've spent quite a lot of blood sweat and tears over the years to make
COPY fast, and we should not sacrifice any of that lightly.

cheers

andrew

--
Andrew Dunstan
EDB: https://www.enterprisedb.com