try {
            final String updateAlias = getUpdateAlias(index);
            final List<String> updateIndices = getIndicesForAlias(updateAlias);
            if (updateIndices.size() != EXPECTED_INDEX_COUNT) {
                if (logger.isDebugEnabled()) {
                    logger.debug("Unexpected number of update indices: expected={}, actual={}, updateAlias={}, indices={}",

        // Create additional update index (making 2 total)
        final String updateAlias = suggester.getIndex() + ".update";
        final String extraIndexName = suggester.getIndex() + ".extra";

        client.admin().indices().prepareCreate(extraIndexName).execute().actionGet();
        client.admin().indices().prepareAliases().addAlias(extraIndexName, updateAlias).execute().actionGet();
        Thread.sleep(50);

     * @param newIndex the new index to point aliases to
     * @return true if the alias update was successful, false otherwise
     */
    public boolean updateAlias(final String newIndex) {
        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        final String updateAlias = fessConfig.getIndexDocumentUpdateIndex();
        final String searchAlias = fessConfig.getIndexDocumentSearchIndex();

                                if (searchEngineClient.copyDocIndex(fromIndex, toIndex, replaceAliases) && replaceAliases
                                        && !searchEngineClient.updateAlias(toIndex)) {
                                    logger.warn("Failed to update aliases for {} and {}", fromIndex, toIndex);
                                }
                            } finally {