Re: [PATCH v4 00/13] midx: incremental multi-pack indexes, part two

[Taylor Blau <me@ttaylorr.com>]

On Mon, Mar 17, 2025 at 10:21:34PM -0400, Jeff King wrote:
> On Fri, Mar 14, 2025 at 04:18:12PM -0400, Taylor Blau wrote:
>
> > This is a new round of my series to implement bitmap support for
> > incremental multi-pack indexes (MIDXs). It has been rebased on current
> > 'master', which is 683c54c999 (Git 2.49, 2025-03-14) at the time of
> > writing.
>
> I read over this and didn't find anything objectionable (I left a few
> comments here and there). I think I've said this before with big
> bitmap/midx series: the biggest issue is that it's hard to know what you
> might have missed. Especially in terms of corner cases. So it all looks
> reasonable to me (including the overall design), but ultimately I think
> it's more fruitful to put it through the paces on real-looking data than
> it is to try to go over every inch of the midx code with a fine-tooth
> comb. And I'd guess the eventual fate here is for this code to get
> exercise on GitHub, which would help with that shaking out.

Thanks for reviewing it, and sorry that this series is so dense to begin
with.

I agree that the proof is really in the pudding here, and the best way
to confirm that we squashed everything is by putting real usage through
the new paths and seeing what shakes out.

I think the main thing that I was hoping for here were two things:

  1. That others thought the overall design and approach are sane, and
     that we're not painting ourselves into a corner.

  2. That we are unlikely to regress non-incremental bitmap usage.

> So mainly I tried to look for things that might hurt the non-incremental
> cases, and didn't see anything (modulo one or two questions about
> micro-optimizations, though I expect the answer there is "nothing big
> enough to measure"). So if this can progress towards the "shaking out"
> phase, and has the potential to hurt only people who turn on the new
> feature, that seems like a good path to me.

...and that's exactly what I got :-).

I'll send a small reroll shortly that addresses the comments from you
and Elijah (thanks, Elijah!) and I'll look forward to hearing what you
think of that round.

Thanks,
Taylor