canvas-lms/db/migrate/20120210173646_remove_irrel...

46 lines
1.5 KiB
Ruby

#
# Copyright (C) 2012 - present Instructure, Inc.
#
# This file is part of Canvas.
#
# Canvas is free software: you can redistribute it and/or modify it under
# the terms of the GNU Affero General Public License as published by the Free
# Software Foundation, version 3 of the License.
#
# Canvas is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
# details.
#
# You should have received a copy of the GNU Affero General Public License along
# with this program. If not, see <http://www.gnu.org/licenses/>.
class RemoveIrrelevantSubmissionMessages < ActiveRecord::Migration[4.2]
tag :predeploy
disable_ddl_transaction!
def self.up
# destroy any submission messages where none of the commenters are
# participants in the conversation. in production, this will remove about
# 7k rows
ConversationMessage.where(<<-CONDITIONS).destroy_all
asset_id IS NOT NULL
AND id NOT IN (
SELECT DISTINCT cm.id
FROM #{ConversationMessage.quoted_table_name} cm,
#{ConversationParticipant.quoted_table_name} cp,
#{SubmissionComment.quoted_table_name} sc
WHERE
cm.asset_id = sc.submission_id
AND cp.conversation_id = cm.conversation_id
AND sc.author_id = cp.user_id
)
CONDITIONS
end
def self.down
raise ActiveRecord::IrreversibleMigration
end
end