From mboxrd@z Thu Jan  1 00:00:00 1970
From: Roel Janssen <roel@gnu.org>
Subject: Re: Performance regression on NFS with new manifest version
Date: Thu, 10 Aug 2017 15:02:33 +0200
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To: Ricardo Wurmus <rekado@elephly.net>
Cc: guix-devel <guix-devel@gnu.org>


Ricardo Wurmus writes:

> Hi Roel,
>
>> Looking into the manifests ($GENERATION_15/manifest and
>> $GENERATION_16/manifest), I noticed that generation 15 uses manifest
>> version 2, and generation 16 uses manifest version 3.
>>
>> What has changed, so that it takes a lot longer to run the same command
>> as before?  (this is probably disk-related, because that is a known
>> cause for trouble on network-mounted stores..)
>
> Commit 55b4715fd4c03e46501f123c5c9bc6072edf12a4 bumped the manifest
> version to 3.  The goal was to represent propagated inputs as manifest
> entries so that we can anticipate conflicts from propagated inputs and
> refuse to build a profile when there would be conflicts.

Thanks for pointing to that commit.  It's much better this way. :-)

So, what makes 'guix package --search-paths' so slow?  It doesn't have
to check for conflicts because that's already done on profile creation
time.  All it has to do is combine the search-path data and output
that..

Anyway, I worked around it by using the $PROFILE/etc/profile file and
unset the environment variables before setting them, which takes less
than a second.

Kind regards,
Roel Janssen