1 files changed, 32 insertions, 0 deletions
diff --git a/db/migrate/20190114184258_migrate_legacy_attachments.rb b/db/migrate/20190114184258_migrate_legacy_attachments.rb
new file mode 100644
index 00000000000..e9fb7952dc9
--- /dev/null
+++ b/db/migrate/20190114184258_migrate_legacy_attachments.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+class MigrateLegacyAttachments < ActiveRecord::Migration[5.0]
+  include Gitlab::Database::MigrationHelpers
+
+  disable_ddl_transaction!
+
+  DOWNTIME = false
+
+  MIGRATION = 'MigrateLegacyUploads'.freeze
+  BATCH_SIZE = 5000
+  DELAY_INTERVAL = 5.minutes.to_i
+
+  class Upload < ActiveRecord::Base
+    self.table_name = 'uploads'
+
+    include ::EachBatch
+  end
+
+  def up
+    Upload.where(uploader: 'AttachmentUploader').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
+
+  # not needed
+  def down
+  end
+end