Subject: Re: [bug#39258] [PATCH v3 1/3] guix: Generate package metadata cache.

From: zimoun <[email-masked]>
Date: Sun, 26 Apr 2020 17:05:48 +0200

Hi Ludo,

On Sun, 26 Apr 2020 at 16:35, Ludovic Courtès <[email-masked]> wrote:

> Realistically though, I understand that things are different on slower
> machines and/or spinning disks.  That’s why I’m interested in seeing how
> Arun’s proposed changes can affect such machines.

I understand. I have done a small benchmark [1] of the 3 ways: the
current, the v2 using Xapian (which is not an option on the long term)
and the v3.

My "slower" machine is at my office... but it provides already
interesting numbers, IMHO.

[1] http://issues.guix.gnu.org/39258#78

> If, as a bonus, it allows us to have an inverted index and thus improve
> the quality of search results, that’s great!

This "issue" is: any improvement on both sides performance and
accuracy would add an somehow extra cost. The question is what is the
maximum users would accept to pay for?

Well, it is complicated as you said. :-)
A trade off between extra cost, maintenance, complexity, etc is not
easy to draw, as you said too elsewhere.
I am seeing all that as experimental: explore ideas to see if they are
worth or not.
And what should be concluded now could change in the (near) future;
for example if the computations of derivations are faster, resulting
on "guix pull" faster, etc..

Cheer,
simon