## Pre-Migration Planning

### 1. Assessment Phase

Before starting migration, assess your current system:

- **Document Count**: Total number of indexed documents
- **Index Size**: Storage requirements for search indices
- **Crawl Sources**: URLs, file shares, databases being indexed
- **Custom Configurations**: URL patterns, security rules, metadata fields
- **Search Features**: Facets, suggestions, security filtering, ranking rules

    /** Logger instance for this factory class. */
    private static final Logger logger = LogManager.getLogger(DataStoreFactory.class);

    /**
     * Map containing registered data store instances indexed by their names and class simple names.
     * All keys are stored in lowercase for case-insensitive lookup.
     */
    protected Map<String, DataStore> dataStoreMap = new LinkedHashMap<>();

    /**

    protected AtomicLong documentSize = new AtomicLong(0);

    /** Total execution time for all operations */
    protected volatile long executeTime = 0;

    /** List of documents waiting to be indexed */
    protected final DocList docList = new DocList();

    /** Maximum size of document requests in bytes */
    protected long maxDocumentRequestSize;

    /** Maximum number of documents to cache before indexing */

        if (ComponentUtil.getFessConfig().isSuggestDocuments()) {
            final CountDownLatch latch = new CountDownLatch(1);

            logger.info("Parsing words from indexed documents.");
            suggestHelper.indexFromDocuments(ret -> {
                logger.info("Success indexing from documents.");
                latch.countDown();
            }, t -> {

    /**
     * Constructs KerberosEncData from encrypted token bytes.
     *
     * @param token the encrypted Kerberos token
     * @param keys map of encryption keys indexed by key type
     * @throws PACDecodingException if decoding fails
     */
    public KerberosEncData(byte[] token, Map<Integer, KerberosKey> keys) throws PACDecodingException {

 */
public class ProcessHelper {
    /** Logger instance for this class */
    private static final Logger logger = LogManager.getLogger(ProcessHelper.class);

    /** Map of running processes indexed by session ID */
    protected final ConcurrentHashMap<String, JobProcess> runningProcessMap = new ConcurrentHashMap<>();

    /** Timeout in seconds for process destruction */
    protected int processDestroyTimeout = 10;

                    deleteOldDocs();
                }
            }
        }

        /**
         * Deletes old documents from the search index.
         * This method removes documents that were indexed in previous
         * crawling sessions for the same data configuration, keeping
         * only the documents from the current session.
         *
         * <p>The deletion process:</p>
         * <ul>

                final String id = crawlingInfoHelper.generateId(dataMap);

                if (logger.isDebugEnabled()) {
                    logger.debug("Searching indexed document: {}", id);
                }
                final Map<String, Object> document = indexingHelper.getDocument(searchEngineClient, id,

     *
     * @param index the name of the OpenSearch index
     * @param type the type of the document (deprecated in newer versions of OpenSearch)
     * @param item the SuggestItem containing the data to be indexed
     * @return a string representing the bulk line for OpenSearch indexing
     * @throws SuggesterException if an I/O error occurs during the creation of the bulk line
     */

     * and performs bulk indexing operations with proper error handling.
     *
     * @param searchEngineClient the search engine client to use for indexing
     * @param docList the list of documents to be indexed
     * @throws SearchEngineClientException if the bulk indexing operation fails
     */
    public void sendDocuments(final SearchEngineClient searchEngineClient, final DocList docList) {
        if (docList.isEmpty()) {