Hi, all I am using lucene 5.5.4.
As trying to make a real-time deletion, I made two singletons, IndexGenerator.java is responsible for the index generating and deletion, and Searcher.java is responsible for doing the search. In order to make the deletion immediately change the search result, I expose the indexWriter used in the generation/deletion period and build the indexSearcher on that. I have checked the documentation of IndexWriter [https://lucene.apache.org/core/5_0_0/core/org/apache/lucene/index/DirectoryReader.html] and quoting: "flushing just moves the internal buffered state in IndexWriter into the index, but these changes are not visible to IndexReader until either commit() or close() is called." After deleting the document, I do a iwriter.flush(); iwriter.commit(); But wired things happen: - query result always the same before or after the deletion happen. it will be not until next time running the programming(which means reloading index files from the disk again, I guess?) that the deletion was made functional. So I think that the deletion was not synced to the reader. Note: Bellowing are the two classes Searcher.java and IndexGenerator.java I do the test with, main method has been put in Searcher.java. There will be a dir in /tmp/test/lucene created by running the code, but when changing the directory to RAMDirectory, searching will /////////////////////////////////////////////////////////////////////////////////////////////////////// ////////////////////////////////Searcher.java//////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////////////////////// import org.apache.lucene.analysis.Analyzer; import org.apache.lucene.analysis.core.SimpleAnalyzer; import org.apache.lucene.document.Document; import org.apache.lucene.index.DirectoryReader; import org.apache.lucene.index.IndexReader; import org.apache.lucene.index.IndexWriter; import org.apache.lucene.queryparser.classic.ParseException; import org.apache.lucene.queryparser.classic.QueryParser; import org.apache.lucene.search.*; import java.io.IOException; public class Searcher { private static Searcher instance = null; private final Analyzer analyzer = new SimpleAnalyzer(); private final IndexReader ireader ; private final IndexSearcher isearcher; public static Searcher getInstance() throws IOException { if(instance == null){ synchronized (Searcher.class){ if(instance == null){ instance = new Searcher(); } } } return instance; } private Searcher() throws IOException { IndexWriter indexWriter = IndexGenerator.getInstance().getWriter(); ireader = DirectoryReader.open(indexWriter, true); System.out.println("total doc num: " + ireader.numDocs()); isearcher = new IndexSearcher(ireader); } public void search(String keyword) throws ParseException, IOException { System.out.println("deleted : " + ireader.hasDeletions() + ", " + "deleted num: " + ireader.numDeletedDocs()); Query query = new QueryParser("text", analyzer).parse(keyword); ScoreDoc[] hits = isearcher.search(query, 100).scoreDocs; for(ScoreDoc hitDoc: hits){ Document doc = isearcher.doc(hitDoc.doc); System.out.println("matching text: '"+doc.get("text")+"'"); } } public static void main(String[] argvs) throws IOException, ParseException { IndexGenerator indexGenerator = IndexGenerator.getInstance(); indexGenerator.rebuildIndex(); Searcher searcher = Searcher.getInstance(); System.out.println("--before delete--"); searcher.search("world"); indexGenerator.deleteById("123456"); System.out.println("--after delete--"); searcher.search("world"); } } ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// //////////////////////////////////IndexGenerator.java/////////////////////////////////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// import org.apache.lucene.analysis.core.SimpleAnalyzer; import org.apache.lucene.document.Document; import org.apache.lucene.document.Field; import org.apache.lucene.document.FieldType; import org.apache.lucene.index.*; import org.apache.lucene.store.FSDirectory; import java.io.IOException; import java.nio.file.Paths; import java.util.HashMap; import java.util.Map; public class IndexGenerator { private static IndexGenerator instance = null; private final Map<String, FieldType> fieldTypes; private final IndexWriter iwriter; SimpleAnalyzer analyzer = new SimpleAnalyzer(); public static IndexGenerator getInstance() throws IOException { if (instance == null) { synchronized (IndexGenerator.class) { if (instance == null) { instance = new IndexGenerator(); } } } return instance; } private IndexGenerator() throws IOException { fieldTypes = new HashMap<>(); FieldType idFt = new FieldType(); idFt.setStored(true); idFt.setOmitNorms(true); idFt.setIndexOptions(IndexOptions.DOCS); idFt.setTokenized(false); idFt.freeze(); fieldTypes.put("_id", idFt); FieldType textFt = new FieldType(); textFt.setStored(true); textFt.setIndexOptions(IndexOptions.DOCS_AND_FREQS_AND_POSITIONS_AND_OFFSETS); fieldTypes.put("text", textFt); IndexWriterConfig config = new IndexWriterConfig(analyzer); config.setOpenMode(IndexWriterConfig.OpenMode.CREATE_OR_APPEND); iwriter = new IndexWriter(FSDirectory.open(Paths.get("/tmp/test/lucene")), config); // iwriter = new IndexWriter(new RAMDirectory(), config); } public void deleteById(String id) { try { Term term = new Term("_id", id); iwriter.deleteDocuments(term); iwriter.flush(); iwriter.commit(); }catch (IOException e){ e.printStackTrace(); } } public IndexWriter getWriter(){ return iwriter; } public void rebuildIndex() throws IOException { iwriter.deleteAll(); iwriter.flush(); iwriter.commit(); Document doc1 = new Document(); Field idField1 = new Field("_id", "123456", fieldTypes.get("_id")); Field textField1 = new Field("text", "hello world", fieldTypes.get("text")); doc1.add(idField1); doc1.add(textField1); iwriter.addDocument(doc1); Document doc2 = new Document(); Field idField2 = new Field("_id", "abcdefg", fieldTypes.get("_id")); Field textField2 = new Field("text", "hi world", fieldTypes.get("text")); doc2.add(idField2); doc2.add(textField2); iwriter.addDocument(doc2); iwriter.flush(); iwriter.commit(); } } --------------------------------------------------------------------- To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org For additional commands, e-mail: java-user-h...@lucene.apache.org
