Re: LogwrtResult contended spinlock

On 2022-Mar-22, Tom Lane wrote:

> I looked briefly at 0001, and I've got to say that I disagree with
> your decision to rearrange the representation of the local LogwrtResult
> copy. It clutters the patch tremendously and makes it hard to
> understand what the actual functional change is. Moreover, I'm
> not entirely convinced that it's a notational improvement in the
> first place.
>
> Perhaps it'd help if you split 0001 into two steps, one to do the
> mechanical change of the representation and then a second patch that
> converts the shared variable to atomics. Since you've moved around
> the places that read the shared variable, that part is subtler than
> one could wish and really needs to be studied on its own.

Hmm, I did it the other way around: first change to use atomics, then
the mechanical change. I think that makes the usefulness of the change
more visible, because before the atomics use the use of the combined
struct as a unit remains sensible.

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