Make the archiver use content_archive.num_present
content_archive.num_present act like a cache for the number of copies where the content is present. This allow to make a much faster request when retrieving the contents that have fewer copies than expected.
This diff works with the commit 9fdbadd0, and they follow a previous discussion in !31 (closed) about this optimization.
Migrated from D93 (view on Phabricator)