Re: Allowing printf("%m") only where it actually works

Hi,

On 2018-09-26 17:41:36 -0400, Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
> > I'm not saying we shouldn't default to our printf - in fact I think we
> > probably past due to use a faster float->string conversion than we
> > portably get from the OS - but I don't think we can default to our
> > sprintf without doing something about the float conversion performance.
> 
> Well, if you're unhappy about snprintf.c's performance, you could review
> https://commitfest.postgresql.org/19/1763/
> so I can push that.  In my tests, that got us down to circa 10% penalty
> for float conversions.

Uh, I can do that, but the fact remains that your commit slowed down
COPY and other conversion intensive workloads by a *significant* amount.
I'm ok helping with improving/winning-back performance, but I do think
the obligation to do so remains with the committer/authors that caused a
performance regression.

Greetings,

Andres Freund