logger.debug("Deleted {} stale documents", deletedDocCount);
                }
                final BulkResponse response =
                        searchEngineClient.addAll(fessConfig.getIndexDocumentUpdateIndex(), docList, (doc, builder) -> {
                            final String configId = (String) doc.get(fessConfig.getIndexFieldConfigId());

        final String docId = form.docId;
        try {
            final QueryBuilder query = QueryBuilders.termQuery(fessConfig.getIndexFieldDocId(), docId);
            searchEngineClient.deleteByQuery(fessConfig.getIndexDocumentUpdateIndex(), query);
            saveInfo(messages -> messages.addSuccessDeleteDocFromIndex(GLOBAL));
        } catch (final Exception e) {
            logger.warn("Failed to process a request.", e);

        final StringBuilder resultBuf = new StringBuilder();

        try {
            final long count = searchEngineClient.updateByQuery(fessConfig.getIndexDocumentUpdateIndex(), option -> {
                if (queryBuilder != null) {
                    option.setQuery(queryBuilder);
                }

        validate(form, messages -> {}, this::asIndexHtml);
        verifyToken(this::asIndexHtml);
        searchEngineClient.flushConfigFiles(() -> {
            final String docIndex = fessConfig.getIndexDocumentUpdateIndex();
            searchEngineClient.admin().indices().prepareClose(docIndex).execute(ActionListener.wrap(res -> {
                logger.info("Closing index: {}", docIndex);
                searchEngineClient.admin()

            context.skipRoleQuery();
        });
        return ComponentUtil.getSearchEngineClient()
                .deleteByQuery(ComponentUtil.getFessConfig().getIndexDocumentUpdateIndex(), queryContext.getQueryBuilder());
    }

    /**
     * Extracts and normalizes language preferences from request parameters or browser locale.
     *

                final boolean isFessIndex = DOC_INDEX.equals(configIndex);
                final String indexName;
                if (isFessIndex) {
                    final boolean exists = existsIndex(fessConfig.getIndexDocumentUpdateIndex());
                    if (!exists) {
                        indexName = generateNewIndexName(configIndex);
                        createIndex(configIndex, indexName);

            }

            try {
                final SearchEngineClient searchEngineClient = ComponentUtil.getSearchEngineClient();
                final String index = fessConfig.getIndexDocumentUpdateIndex();
                searchEngineClient.admin().indices().prepareRefresh(index).execute().actionGet();
                final long numOfDeleted = searchEngineClient.deleteByQuery(index, queryBuilder);

                                        upsertMap.put(fessConfig.getIndexFieldClickCount(), count);
                                        return new UpdateRequest(fessConfig.getIndexDocumentUpdateIndex(), id).script(script)
                                                .upsert(upsertMap);
                                    }
                                    return null;
                                })

     * The value is, e.g. fess.update <br>
     * comment: Index name for update documents.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getIndexDocumentUpdateIndex();

    /**
     * Get the value for the key 'index.document.suggest.index'. <br>
     * The value is, e.g. fess <br>
     * comment: Index name for suggest documents.