Question

Playing around with Lucene. Trying to make my changes visible for other reading threads. Without rebuilding index. For that purpose i use SearcherManager class.

Creation of manager

Directory index = new SimpleFSDirectory(new File(LUCENE_INDEX_PATH));
w = new IndexWriter(index, config);
indexReader = IndexReader.open(w, true);
manager = new SearcherManager(w, true, null, null);

Update request

w.updateDocument(t, document);
manager.maybeReopen(); // openIfChanged same behavior
w.commit();

Search request

IndexSearcher searcher = manager.acquire();
try {
    return performSearch(query, searcher, skip, limit);
} finally {
    manager.release(searcher);
    searcher = null;
}

Changes are flushed to disc, but new search request see them only after application restart (recreation of index). Looks like IndexSearcher still point to old Index.

Answer 1

You don’t need to open your own IndexReader; just create the SearcherManager (from your IndexWriter) then use acquire/release from it, to get a searcher/reader.

After adding/deleting docs with the writer, you should call maybeReopen, and then the next time you call SearcherManager.acquire the returned searcher will reflect the changes. It’s best to use a background thread (ie, not a thread doing searching) to index docs and call maybeReopen.

You don’t need to call IndexWriter.commit to make changes visible — only call this when you require durability (ie, that all changes are safely on disk and will survive OS/JVM crash, power loss, kill -9, etc.).