resultBuf.append(e.getMessage()).append("\n");
        }

        // purge search logs
        try {
            final int days = ComponentUtil.getFessConfig().getPurgeSearchLogDay();
            if (days >= 0) {
                searchLogService.deleteBefore(days);
            } else {
                resultBuf.append("Skipped to purge search logs.\n");
            }
        } catch (final Exception e) {