GNU bug report logs - #78194
`guix pull --list-generations' is extremely slow

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Ian Eure <ian <at> retrospec.tv>
To: bug-guix <at> gnu.org
Subject: `guix pull --list-generations' is extremely slow
Date: Thu, 01 May 2025 08:35:21 -0700

I’ve been frustrated by this before, but decided to measure 
things:

`guix home list-generations' takes 3.535s to list 28 items.
`guix system list-generations' takes 1.406s to list 35 items.
`guix pull --list-generations' takes 232.599s to list 41 items.

Why is `guix pull --list-generations' >100x slower than `guix 
system list-generations'?

Thanks,

 -- Ian

Message #8 received at 78194 <at> debbugs.gnu.org (full text, mbox):

From: Ludovic Courtès <ludo <at> gnu.org>
To: Ian Eure <ian <at> retrospec.tv>
Cc: 78194 <at> debbugs.gnu.org
Subject: Re: bug#78194: `guix pull --list-generations' is extremely slow
Date: Wed, 14 May 2025 18:33:35 +0200

Hi,

Ian Eure <ian <at> retrospec.tv> writes:

> I’ve been frustrated by this before, but decided to measure things:
>
> `guix home list-generations' takes 3.535s to list 28 items.
> `guix system list-generations' takes 1.406s to list 35 items.
> `guix pull --list-generations' takes 232.599s to list 41 items.
>
> Why is `guix pull --list-generations' >100x slower than `guix system
> list-generations'?

Because for each pair of generations, it shows the corresponding news
entries (as per ‘guix pull --news’), and that part is quite expensive
because it involves a Git log traversal.

I think we should (1) optimize the news code (that’s
‘channel-news-for-commit’), and (2) if that’s not enough consider
keeping it off by default in ‘guix pull --list-generations’.

Thoughts?

Ludo’.

Message #11 received at 78194 <at> debbugs.gnu.org (full text, mbox):

From: Ludovic Courtès <ludo <at> chbouib.org>
To: Ludovic Courtès <ludo <at> gnu.org>
Cc: 78194 <at> debbugs.gnu.org, Ian Eure <ian <at> retrospec.tv>
Subject: Re: bug#78194: `guix pull --list-generations' is extremely slow
Date: Wed, 14 May 2025 22:28:37 +0200

Ludovic Courtès <ludo <at> gnu.org> writes:

> Because for each pair of generations, it shows the corresponding news
> entries (as per ‘guix pull --news’), and that part is quite expensive
> because it involves a Git log traversal.
>
> I think we should (1) optimize the news code (that’s
> ‘channel-news-for-commit’), and (2) if that’s not enough consider
> keeping it off by default in ‘guix pull --list-generations’.

That turned out to be easier than I thought, see
<https://issues.guix.gnu.org/78432>, which makes it 10–20x faster.

Ludo’.

Message #16 received at 78194-done <at> debbugs.gnu.org (full text, mbox):

From: Andreas Enge <andreas <at> enge.fr>
To: 78194-done <at> debbugs.gnu.org
Subject: Close
Date: Sun, 15 Jun 2025 10:49:39 +0200

This has apparently been solved, see the last message; closing.

Andreas

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