Subject: [bug#50040] [PATCH 0/2] publish: Always render nar/narinfo during backing.

From: Ludovic Courtès <[email-masked]>
Date: Wed, 01 Sep 2021 22:48:42 +0200

Hello!

Mathieu Othacehe <[email-masked]> skribis:

>> Did you manage to come up with a way to synthetically reproduce the
>> problem?
>
> Yes but it is rather complex. I managed to restart a lot of builds at
> the same time by running SQL queries on the Cuirass database.

OK.

[...]

>>      But look, ‘read-derivation-from-file’ is called just to fill in the
>>      “System” field, which is not used anywhere (not a single caller of
>>      ‘narinfo-system’), so we could just as well remove it and see how
>>      it behaves.
>
> Yes, I'll propose a patch to remove it.

Neat.

>> Anyway, that the main thread is blocking while this happens is certainly
>> a problem, so this patch looks like an improvement.  That we have to use
>> the ‘http-write’ hack isn’t great, but I think it’s OK, unless we want
>> to switch to Fibers.
>
> I think that applying this patchset + removing read-derivation-from-file
> call + increasing Nginx timeouts could be a good start. However, I will
> be mostly afk for about 3 weeks so unable to monitor the publish server
> on Berlin and fix potential regressions. Maybe we should wait until
> then.

Yes, sounds safer.  Removing the “System” bit from narinfos produced by
‘guix publish’ should be fine, though.

Thanks!

Ludo’.