Re: weird quadratic reftable behavior, was: Re: [PATCH 3/3] t5551: pack refs after creating many tags

[Patrick Steinhardt <ps@pks.im>]

On Fri, Jul 03, 2026 at 02:09:45PM +0200, Kristofer Karlsson wrote:
> On Wed, 1 Jul 2026 at 12:07, Patrick Steinhardt <ps@pks.im> wrote:
> > >
> > > I can send a proper patch if needed/wanted, but I might have missed
> > > something silly here.
> >
> > Nice gains. I certainly think it would make sense to polish this a bit
> > and then cast it into a patch.
> >
> > Patrick
> 
> I have a small draft here https://github.com/gitgitgadget/git/pull/2166
> but I am honestly not sure if it's worth submitting as a patch - the
> change is somewhat small, but spread out, and I failed to properly
> reproduce the performance win in any realistic scenario (I had to
> disable compaction to see the improvement).

An easy scenario where you don't have to disable compaction would be
what Peff posted: you create X references and then delete all of them.
That shouldn't result in compaction and directly hits the case that we
care about.

> I would want to rely on your expertise to know if this change
> would be valuable to discuss as a patch at all.

If we can demonstrate a significant improvement in the above case then
it would be worth it, I guess.

Patrick