Hey,

The Guix Data Service has Guix compute lots of derivations, and then it
loads the data in to a database. I'm having some issues with the garbage
collector though, as sometimes it removes data from the disk before I've
had a chance to read it (at least I think this is what's happening, I
think this job failed for this reason [1]).

1: http://data.guix.gnu.org/job/10638

I'm not quite sure what the best strategy is to combat this? I had a
look, and I couldn't see how to acquire a lock to prevent the garbage
collector from running. I thought about registering thousands of gc
roots, but that seems to just move the race a bit, as there's still a
period between generating the derivation and registering the root where
it can be deleted.

Any ideas?

Thanks,

Chris