Re: Locking B-tree leafs immediately in exclusive mode

On Fri, Jul 27, 2018 at 12:30 AM Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> On 26 July 2018 at 20:59, Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru> wrote:
>
> > Great, thank you! So, I think the regression is demystified. We can
> > now conclude that on our benchmarks this patch doesn't cause
> > performance regression larger than measurement error. But in some
> > cases it shows huge performance benefit.
> >
> > So, I'm going to commit this, if no objections.
>
> +1 to commit.
>
> What will the commit message be?
>
> For me, this is about reducing contention on index leaf page hotspots,
> while at the same time reducing the path length of lock acquisition on
> leaf pages

So, reducing path length of lock acquisition is particular technical
change made, while reducing contention on index leaf pages is a
result. I think that reducing path length of lock acquisition should
be mentioned in title of commit message, while contention reduction
should be mentioned in the body of commit message, because it's
motivation of this commit. If we would have release notes item for
this commit, it should also mention contention reduction, because it's
a user-visible effect of this commit.

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Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company