Re: LogwrtResult contended spinlock - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: LogwrtResult contended spinlock
Date
Msg-id 202203221611.hqbjdinzsbu2@alvherre.pgsql
Whole thread Raw
In response to Re: LogwrtResult contended spinlock  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: LogwrtResult contended spinlock
Re: LogwrtResult contended spinlock
List pgsql-hackers
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.

-- 
Álvaro Herrera        Breisgau, Deutschland  —  https://www.EnterpriseDB.com/
Officer Krupke, what are we to do?
Gee, officer Krupke, Krup you! (West Side Story, "Gee, Officer Krupke")

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