1 files changed, 39 insertions, 0 deletions
diff --git a/lib/gitlab/background_migration/update_timelogs_null_spent_at.rb b/lib/gitlab/background_migration/update_timelogs_null_spent_at.rb
new file mode 100644
index 00000000000..b61f2ee7f4c
--- /dev/null
+++ b/lib/gitlab/background_migration/update_timelogs_null_spent_at.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module BackgroundMigration
+    # Class to populate spent_at for timelogs
+    class UpdateTimelogsNullSpentAt
+      include Gitlab::Database::DynamicModelHelpers
+
+      BATCH_SIZE = 100
+
+      def perform(start_id, stop_id)
+        define_batchable_model('timelogs', connection: connection)
+            .where(spent_at: nil, id: start_id..stop_id)
+            .each_batch(of: 100) do |subbatch|
+          batch_start, batch_end = subbatch.pick('min(id), max(id)')
+
+          update_timelogs(batch_start, batch_end)
+        end
+      end
+
+      def update_timelogs(batch_start, batch_stop)
+        execute(<<~SQL)
+          UPDATE timelogs
+          SET spent_at = created_at
+          WHERE spent_at IS NULL
+          AND timelogs.id BETWEEN #{batch_start} AND #{batch_stop};
+        SQL
+      end
+
+      def connection
+        @connection ||= ApplicationRecord.connection
+      end
+
+      def execute(sql)
+        connection.execute(sql)
+      end
+    end
+  end
+end