Re: wal stats questions

At Mon, 29 Mar 2021 11:09:00 +0900 (JST), Kyotaro Horiguchi <horikyota.ntt@gmail.com> wrote in 
> At Fri, 26 Mar 2021 10:07:45 -0700, Andres Freund <andres@anarazel.de> wrote in 
> > Hi,
> > 
> > On 2021-03-25 16:37:10 +0900, Kyotaro Horiguchi wrote:
> > > On the other hand, the counters are incremented in XLogInsertRecord()
> > > and I think we don't want add instructions there.
> > 
> > I don't really buy this. Setting a boolean to true, in a cacheline
> > you're already touching, isn't that much compared to all the other stuff
> > in there. The branch to check if wal stats timing etc is enabled is much
> > more expensive.  I think we should just set a boolean to true and leave
> > it at that.
> 
> Hmm. Yes, I agree to you in that opinion.  I (remember I) was told not

It might sound differently.. To be precise, "I had the same opinion
with you".

> to add even a cycle to the hot path as far as we can avoid when I
> tried something like that.
> 
> So I'm happy to +1 for that if it is the consensus here, since it is
> cleaner.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center