bug#30290: guix-daemon slows to a crawl when a substitute server is offline

[Ludovic Courtès]

Hi,

Maxim Cournoyer <maxim.cournoyer@gmail.com> skribis:

> When a substitute server used by guix-daemon is offline, the daemon will
> keep attempting to connect to it, even when it shouldn't need any data
> (ran 'sudo guix system reconfigure my-config.scm' multiple times in a
> row.
>
> With the disconnected server (bayfront in my case), that command would
> take close to 8 minutes, with many system calls like:
>
> connect(14, {sa_family=AF_INET, sin_port=htons(443), 
> sin_addr=inet_addr("141.255.128.56")}, 16) = -1 EINPROGRESS
>
> which wasted 5 seconds each time.

Is it still a problem?  Commit 4f5234be0378368e6af25925db46612838d25e58
(Nov. 2019) added a table of unreachable hosts.  That way, a ‘guix
substitute --query’ process won’t retry connections to an unreachable
host.

Ludo’.