select entries.target
from
(
select swh_directory_walk(revision.directory)
from snapshot tablesample system (0.001)
inner join snapshot_branches using snapshot_id
inner join snapshot_branch using branch_id
inner join release on (snapshot_branch.target = release.id
and snapshot_branch.target_type = 'release')
inner join revision on (release.target = revision.id
and release.target_type = 'revision')
) as entries
where entries.type = 'file';