1 files changed, 30 insertions, 0 deletions
diff --git a/db/migrate/20180309121820_reschedule_commits_count_for_merge_request_diff.rb b/db/migrate/20180309121820_reschedule_commits_count_for_merge_request_diff.rb
new file mode 100644
index 00000000000..990759104b0
--- /dev/null
+++ b/db/migrate/20180309121820_reschedule_commits_count_for_merge_request_diff.rb
@@ -0,0 +1,30 @@
+class RescheduleCommitsCountForMergeRequestDiff < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  MIGRATION = 'AddMergeRequestDiffCommitsCount'.freeze
+  BATCH_SIZE = 5000
+  DELAY_INTERVAL = 5.minutes.to_i
+
+  class MergeRequestDiff < ActiveRecord::Base
+    self.table_name = 'merge_request_diffs'
+
+    include ::EachBatch
+  end
+
+  disable_ddl_transaction!
+
+  def up
+    say 'Populating the MergeRequestDiff `commits_count` (reschedule)'
+
+    execute("SET statement_timeout TO '60s'") if Gitlab::Database.postgresql?
+
+    MergeRequestDiff.where(commits_count: nil).each_batch(of: BATCH_SIZE) do |relation, index|
+      start_id, end_id = relation.pluck('MIN(id), MAX(id)').first
+      delay = index * DELAY_INTERVAL
+
+      BackgroundMigrationWorker.perform_in(delay, MIGRATION, [start_id, end_id])
+    end
+  end
+end