logger.error("IndexUpdater is terminated.", e);
            } else if (logger.isInfoEnabled()) {
                logger.info("IndexUpdater is terminated.");
            }
            forceStop();
        } catch (final Throwable t) {
            if (ComponentUtil.available()) {
                logger.error("IndexUpdater is terminated.", t);
            } else if (logger.isDebugEnabled()) {

        }

        // run index update
        final IndexUpdater indexUpdater = ComponentUtil.getIndexUpdater();
        indexUpdater.setName("IndexUpdater");
        indexUpdater.setPriority(indexUpdaterPriority);
        indexUpdater.setSessionIdList(sessionIdList);
        indexUpdater.setDaemon(true);
        indexUpdater.setCrawlerList(crawlerList);
        getAvailableBoostDocumentRuleList().forEach(rule -> {