1 files changed, 45 insertions, 0 deletions
diff --git a/db/migrate/20180711103851_drop_duplicate_protected_tags.rb b/db/migrate/20180711103851_drop_duplicate_protected_tags.rb
new file mode 100644
index 00000000000..8fa2137551e
--- /dev/null
+++ b/db/migrate/20180711103851_drop_duplicate_protected_tags.rb
@@ -0,0 +1,45 @@
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class DropDuplicateProtectedTags < ActiveRecord::Migration
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  BATCH_SIZE = 1000
+
+  class Project < ActiveRecord::Base
+    self.table_name = 'projects'
+
+    include ::EachBatch
+  end
+
+  class ProtectedTag < ActiveRecord::Base
+    self.table_name = 'protected_tags'
+  end
+
+  def up
+    Project.each_batch(of: BATCH_SIZE) do |projects|
+      ids = ProtectedTag
+        .where(project_id: projects)
+        .group(:name, :project_id)
+        .select('max(id)')
+
+      tags = ProtectedTag
+        .where(project_id: projects)
+        .where.not(id: ids)
+
+      if Gitlab::Database.postgresql?
+        tags.delete_all
+      else
+        # Workaround needed for MySQL
+        sql = "SELECT id FROM (#{tags.to_sql}) protected_tags"
+
+        ProtectedTag.where("id IN (#{sql})").delete_all # rubocop:disable GitlabSecurity/SqlInjection
+      end
+    end
+  end
+
+  def down
+  end
+end