return null;
            }
            final String requestsPerSecond = String.valueOf(fessConfig.getIndexReindexSizeAsInteger() * fessConfig.availableProcessors());
            logger.info("Set requests_per_second to {}", requestsPerSecond);
            return requestsPerSecond;
        }
        return value;
    }

    /**
     * Creates a new index with default settings.