Migrate issues authored by deleted user to the Ghost user

2 files changed, 50 insertions, 0 deletions

diff --git a/db/migrate/20170825104051_migrate_issues_to_ghost_user.rb b/db/migrate/20170825104051_migrate_issues_to_ghost_user.rb
new file mode 100644
index 00000000000..294141e4fdb
--- /dev/null
+++ b/db/migrate/20170825104051_migrate_issues_to_ghost_user.rb
@@ -0,0 +1,36 @@
+class MigrateIssuesToGhostUser < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  class User < ActiveRecord::Base
+    self.table_name = 'users'
+  end
+
+  class Issue < ActiveRecord::Base
+    self.table_name = 'issues'
+
+    include ::EachBatch
+  end
+
+  def reset_column_in_migration_models
+    ActiveRecord::Base.clear_cache!
+
+    ::User.reset_column_information
+  end
+
+  def up
+    reset_column_in_migration_models
+
+    # we use the model method because rewriting it is too complicated and would require copying multiple methods
+    ghost_id = ::User.ghost.id
+
+    Issue.where('NOT EXISTS (?)', User.unscoped.select(1).where('issues.author_id = users.id')).each_batch do |relation|
+      relation.update_all(author_id: ghost_id)
+    end
+  end
+
+  def down
+  end
+end
diff --git a/db/migrate/20170901071411_add_foreign_key_to_issue_author.rb b/db/migrate/20170901071411_add_foreign_key_to_issue_author.rb
new file mode 100644
index 00000000000..ab6e9fb565a
--- /dev/null
+++ b/db/migrate/20170901071411_add_foreign_key_to_issue_author.rb
@@ -0,0 +1,14 @@
+class AddForeignKeyToIssueAuthor < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_foreign_key(:issues, :users, column: :author_id, on_delete: :nullify)
+  end
+
+  def down
+    remove_foreign_key(:issues, column: :author_id)
+  end
+end