Add nested groups support on data leveldz-nested-groups

* add parent_id field to namespaces table to store relation with nested groups
* create routes table to keep information about full path of every group and project
* project/group lookup by full path from routes table

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/db/migrate/20161202152031_remove_duplicates_from_routes.rb b/db/migrate/20161202152031_remove_duplicates_from_routes.rb
new file mode 100644
index 00000000000..510796e05f2
--- /dev/null
+++ b/db/migrate/20161202152031_remove_duplicates_from_routes.rb
@@ -0,0 +1,28 @@
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class RemoveDuplicatesFromRoutes < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def up
+    select_all("SELECT path FROM #{quote_table_name(:routes)} GROUP BY path HAVING COUNT(*) > 1").each do |row|
+      path = connection.quote(row['path'])
+      execute(%Q{
+        DELETE FROM #{quote_table_name(:routes)}
+        WHERE path = #{path}
+        AND id != (
+          SELECT id FROM (
+            SELECT max(id) AS id
+            FROM #{quote_table_name(:routes)}
+            WHERE path = #{path}
+          ) max_ids
+        )
+      })
+    end
+  end
+
+  def down
+  end
+end