+:edge_perm => %{
+case (edges.edge_id = '#{edge_id}')
+ when true then #{perm_level}
+ else edges.val
+ end
+}
+} }) as pq),
+
+/*
+ Because users always have permission on themselves, this
+ query also makes sure those permission rows are always
+ returned.
+*/
+temptable_perms as (
+ select * from origin_user_perms
+ union all
+ select target_uuid as user_uuid, target_uuid, 3, true
+ from origin_user_perms
+ where origin_user_perms.target_uuid like '_____-tpzed-_______________' and
+ origin_user_perms.target_uuid != '#{perm_origin_uuid}'
+),
+
+/*
+ Now that we have recomputed a set of permissions, delete any
+ rows from the materialized_permissions table where (target_uuid,
+ user_uuid) is not present or has perm_level=0 in the recomputed
+ set.
+*/
+delete_rows as (
+ delete from #{PERMISSION_VIEW} where
+ user_uuid='#{perm_origin_uuid}' and
+ not exists (select 1 from temptable_perms
+ where target_uuid=#{PERMISSION_VIEW}.target_uuid and
+ user_uuid='#{perm_origin_uuid}' and
+ val>0)
+)
+
+/*
+ Now insert-or-update permissions in the recomputed set. The
+ WHERE clause is important to avoid redundantly updating rows
+ that haven't actually changed.
+*/
+insert into #{PERMISSION_VIEW} (user_uuid, target_uuid, perm_level, traverse_owned)
+ select user_uuid, target_uuid, val as perm_level, traverse_owned from temptable_perms where val>0
+on conflict (user_uuid, target_uuid) do update
+set perm_level=EXCLUDED.perm_level, traverse_owned=EXCLUDED.traverse_owned
+where #{PERMISSION_VIEW}.user_uuid=EXCLUDED.user_uuid and
+ #{PERMISSION_VIEW}.target_uuid=EXCLUDED.target_uuid and
+ (#{PERMISSION_VIEW}.perm_level != EXCLUDED.perm_level or
+ #{PERMISSION_VIEW}.traverse_owned != EXCLUDED.traverse_owned);