writeTimeToSessionInfo(crawlingInfoHelper, Constants.WEB_FS_CRAWLER_START_TIME);
                    webFsIndexHelper.crawl(options.sessionId, webConfigIdList, fileConfigIdList);
                    writeTimeToSessionInfo(crawlingInfoHelper, Constants.WEB_FS_CRAWLER_END_TIME);
                }, WEB_FS_CRAWLING_PROCESS);
                webFsCrawlerThread.start();
            }

            if (runAll || dataConfigIdList != null) {

                            logger.warn("Failed to delete {}.", tempFile.getAbsolutePath());
                        }
                    }
                }).start();
                saveInfo(messages -> messages.addSuccessInstallPlugin(GLOBAL, form.jarFile.getFileName()));
            } else {
                final Artifact artifact = getArtifactFromInstallForm(form);

    public static final String CRAWLER_ERRORS = "CrawlerErrors";

    public static final String CRAWLER_START_TIME = "CrawlerStartTime";

    public static final String CRAWLER_END_TIME = "CrawlerEndTime";

    public static final String CRAWLER_EXEC_TIME = "CrawlerExecTime";

    public static final String WEB_FS_CRAWLER_START_TIME = "WebFsCrawlStartTime";

    public static final String WEB_FS_CRAWLER_END_TIME = "WebFsCrawlEndTime";

        if (pageNumber != null && pageNumber > 0) {
            pageNumber = pageNumber + move;
            if (pageNumber < 1) {
                pageNumber = 1;
            }
            form.start = (pageNumber - 1) * form.getPageSize();
        }
        return doSearch(form);
    }

    // -----------------------------------------------------
    // Confirm
    // -------

    @Execute

        protected final SearchRequestBuilder searchRequestBuilder;
        protected String query;
        protected String[] responseFields;
        protected int offset = Constants.DEFAULT_START_COUNT;
        protected int size = Constants.DEFAULT_PAGE_SIZE;
        protected GeoInfo geoInfo;
        protected FacetInfo facetInfo;
        protected HighlightInfo highlightInfo;

    protected long queryTime;

    // for testing
    protected QueryResponseList(final List<Map<String, Object>> documentList, final int start, final int pageSize, final int offset) {
        this.parent = documentList;
        this.offset = offset;
        this.start = start;
        this.pageSize = pageSize;
    }

            }
            int start = startPosition - offset;
            if (start < 0) {
                start = 0;
            }
            if (logger.isDebugEnabled()) {
                logger.debug("start:{} -> start:{} with offset:{}.", startPosition, start, offset);
            }
            final SearchRequestParams reqParams = new SearchRequestParamsWrapper(params, start, pageSize);

    /** The key of the message: Start Crawling */
    public static final String LABELS_wizard_start_crawling_title = "{labels.wizard_start_crawling_title}";

    /** The key of the message: Crawler */
    public static final String LABELS_wizard_start_crawler_title = "{labels.wizard_start_crawler_title}";

    /** The key of the message: To click "Start Crawling" button, you can start a crawling now. */

                return startPosition;
            }

            final String start = request.getParameter("start");
            if (StringUtil.isBlank(start)) {
                startPosition = fessConfig.getPagingSearchPageStartAsInteger();
            } else {
                try {
                    startPosition = Integer.parseInt(start);
                } catch (final NumberFormatException e) {

                    }
                }
            }
            if (!taskList.isEmpty()) {
                storeQueue(taskList);
            }
        }, "ThumbnailGenerator");
        thumbnailQueueThread.start();
    }

    @PreDestroy
    public void destroy() {
        generating = false;
        thumbnailQueueThread.interrupt();
        try {
            thumbnailQueueThread.join(10000);