Reset merge status from mergeable MRs

Adds migrations to reset the merge_status of opened,
mergeable MRs. That's required by
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/28513
so we're able to sync the status update along merge-ref,
without leaving MRs with a stale merge-ref.

1 files changed, 30 insertions, 0 deletions

diff --git a/db/post_migrate/20190528180441_enqueue_reset_merge_status.rb b/db/post_migrate/20190528180441_enqueue_reset_merge_status.rb
new file mode 100644
index 00000000000..1b668d85bac
--- /dev/null
+++ b/db/post_migrate/20190528180441_enqueue_reset_merge_status.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class EnqueueResetMergeStatus < ActiveRecord::Migration[5.1]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  BATCH_SIZE = 10_000
+  MIGRATION = 'ResetMergeStatus'
+  DELAY_INTERVAL = 5.minutes.to_i
+
+  disable_ddl_transaction!
+
+  def up
+    say 'Scheduling `ResetMergeStatus` jobs'
+
+    # We currently have around 135_000 opened, mergeable MRs in GitLab.com. This iteration
+    # will schedule around 13 batches of 10_000 MRs, which should take around 1 hour to
+    # complete.
+    relation = MergeRequest.where(state: 'opened', merge_status: 'can_be_merged')
+
+    relation.each_batch(of: BATCH_SIZE) do |batch, index|
+      range = batch.pluck('MIN(id)', 'MAX(id)').first
+
+      BackgroundMigrationWorker.perform_in(index * DELAY_INTERVAL, MIGRATION, range)
+    end
+  end
+end