1 files changed, 29 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..d73b0847506
--- /dev/null
+++ b/db/migrate/20161202152031_remove_duplicates_from_routes.rb
@@ -0,0 +1,29 @@
+# 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
+    # We can skip this migration when running a PostgreSQL database because
+    # we use an optimized query in the "FillProjectsRoutesTable" migration
+    # to fill these values that avoid duplicate entries in the routes table.
+    return unless Gitlab::Database.mysql?
+
+    execute <<-EOF
+      DELETE duplicated_rows.*
+      FROM routes AS duplicated_rows
+        INNER JOIN (
+          SELECT path, MAX(id) as max_id
+          FROM routes
+          GROUP BY path
+          HAVING COUNT(*) > 1
+        ) AS good_rows ON good_rows.path = duplicated_rows.path AND good_rows.max_id <> duplicated_rows.id;
+    EOF
+  end
+
+  def down
+  end
+end