Issue #3319054: Install hook assumes there's enough memory to load all submissions at once.

    }

  }

  // Update existing values.

  $webform_submissions = WebformSubmission::loadMultiple();

  $submission_ids = \Drupal::entityTypeManager()->getStorage('webform_submission')

    ->getQuery()->accessCheck(false)->execute();

  $slice_size = 100;

  $start = 0;

  while ($start < count($submission_ids)) {

    $webform_submissions = WebformSubmission::loadMultiple(array_slice($submission_ids, $start, $slice_size));

    foreach ($webform_submissions as $webform_submission) {

      /**

       * @var \Drupal\webform\Entity\WebformSubmission $webform_submission

        $webform_submission->save();

      }

    }

    $start += $slice_size;

  }

}