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Lucene Incremental Update of Index

I'm a bit new to Lucene, I am using a huge database which I indexed previously. The problem is that it is not an efficient way to index the whole table/ database every time if something new is added into it. I'm using lucene3.6.2. I want to make an indexing function which adds the new data to the existing Lucene indexed files, without the need to updateDocument(or delete and re-index in lucene). I mean to say it should not create new files to store the new documents rather should insert them into the previous index files without deleting the previous data inside the index files and without re-indexing the whole database. Whose index should start from the last index location of the previously indexed item, and should be searchable along with the previously generated indexes. This is my indexer code for creating index:
public String TestIndex() throws IOException,SQLException
{
System.out.println("preparing dictionary");
String output="";
Long i=0l;
ResultSet rs = null;
URL u = this.getClass().getClassLoader(). getResource(SearchConstant.INDEX_DIRECTORY_DICTIONARYDETAILS);
String dirLoc = u.getPath().replace("%20", " ");
Directory index = FSDirectory.open(new File(dirLoc)); //new RAMDirectory();
StandardAnalyzer analyzer = new StandardAnalyzer(Version.LUCENE_30);
IndexWriterConfig config = new IndexWriterConfig(Version.LUCENE_30,analyzer);
config.setOpenMode(OpenMode.CREATE);
IndexWriter w = new IndexWriter(index, config);
try {
String SQL = "Select * from test";
cm = new DbUtility();
rs = cm.getData(SQL);
// 1. create the index
while (rs.next()) {
Document doc = new Document();
doc.add(new Field("id",rs.getObject(1).toString() , Field.Store.YES, Field.Index.ANALYZED));
doc.add(new Field("Heading",rs.getObject(2).toString() , Field.Store.YES, Field.Index.ANALYZED));
w.addDocument(doc);
i = i + 1;
}
System.out.println("I " + i.toString());
}
catch (Exception e) {
System.out.println("I in Error " + i.toString());
System.out.println("Error while retrieving data: "+e.getMessage());
}
w.close();
rs.close();
return output;
}

"TokenStream contract violation: close() call missing" when calling addDocument

I'm using Lucene's features to build a simple way to match similar words within a text.
My idea is to have have an Analyzer running on my text to provide a TokenStream, and for each token I run a FuzzyQuery to see if I have a match in my index. If not I just index a new Document containing just the new unique word.
Here's what I'm getting tho:
Exception in thread "main" java.lang.IllegalStateException: TokenStream contract violation: close() call missing
at org.apache.lucene.analysis.Tokenizer.setReader(Tokenizer.java:90)
at org.apache.lucene.analysis.Analyzer$TokenStreamComponents.setReader(Analyzer.java:411)
at org.apache.lucene.analysis.standard.StandardAnalyzer$1.setReader(StandardAnalyzer.java:111)
at org.apache.lucene.analysis.Analyzer.tokenStream(Analyzer.java:165)
at org.apache.lucene.document.Field.tokenStream(Field.java:568)
at org.apache.lucene.index.DefaultIndexingChain$PerField.invert(DefaultIndexingChain.java:708)
at org.apache.lucene.index.DefaultIndexingChain.processField(DefaultIndexingChain.java:417)
at org.apache.lucene.index.DefaultIndexingChain.processDocument(DefaultIndexingChain.java:373)
at org.apache.lucene.index.DocumentsWriterPerThread.updateDocument(DocumentsWriterPerThread.java:231)
at org.apache.lucene.index.DocumentsWriter.updateDocument(DocumentsWriter.java:478)
at org.apache.lucene.index.IndexWriter.updateDocument(IndexWriter.java:1562)
at org.apache.lucene.index.IndexWriter.addDocument(IndexWriter.java:1307)
at org.myPackage.MyClass.addToIndex(MyClass.java:58)
Relevant code here:
// Setup tokenStream based on StandardAnalyzer
TokenStream tokenStream = analyzer.tokenStream(TEXT_FIELD_NAME, new StringReader(input));
tokenStream = new StopFilter(tokenStream, EnglishAnalyzer.getDefaultStopSet());
tokenStream = new ShingleFilter(tokenStream, 3);
tokenStream.addAttribute(CharTermAttribute.class);
tokenStream.reset();
...
// Iterate and process each token from the stream
while (tokenStream.incrementToken()) {
CharTermAttribute charTerm = tokenStream.getAttribute(CharTermAttribute.class);
processWord(charTerm.toString());
}
...
// Processing a word means looking for a similar one inside the index and, if not found, adding this one to the index
void processWord(String word) {
...
if (DirectoryReader.indexExists(index)) {
reader = DirectoryReader.open(index);
IndexSearcher searcher = new IndexSearcher(reader);
TopDocs searchResults = searcher.search(query, 1);
if (searchResults.totalHits > 0) {
Document foundDocument = searcher.doc(searchResults.scoreDocs[0].doc);
super.processWord(foundDocument.get(TEXT_FIELD_NAME));
} else {
addToIndex(word);
}
} else {
addToIndex(word);
}
...
}
...
// Create a new Document to index the provided word
void addWordToIndex(String word) throws IOException {
Document newDocument = new Document();
newDocument.add(new TextField(TEXT_FIELD_NAME, new StringReader(word)));
indexWriter.addDocument(newDocument);
indexWriter.commit();
}
The exception seems to tell that I should close the TokenStream before adding things to the index, but this doesn't really make sense to me because how are index and TokenStream related? I mean, index just receives a Document containing a String, having the String coming from a TokenStream should be irrelevant.
Any hint on how to solve this?

The problem is in your reuse of the same analyzer that the IndexWriter is trying to use. You have a TokenStream open from that analyzer, and then you try to index a document. That document needs to be analyzed, but the analyzer finds it's old TokenStream is still open, and throws an exception.
To fix it, you could create a new, separate analyzer for processing and testing the string, instead of using the one that IndexWriter is using.

Set indexed attribute of a lucene field?

I have a big lucene index produced by 3rd party.
I want to search over a field which is not indexed. Is it possible to re-create the index with that field being now indexed?

I am assuming that field is stored right? If not, you are out of luck.
If it is stored, you have several options, I think the easiest would be:
dump all docs as csv output (see here)
change that field's schema to indexed=true
then reindex all of them (csv output can be used for update as well)

Solved myself, just using an index reader and a writer.
I dunno if it's the proper way. The field was a string field (stored), so for this case, it just worked.
IndexReader reader = IndexReader.open(...);
IndexWriter writer = new IndexWriter(...);
for(int i = 0; i < reader.maxDoc(); i++) {
if(reader.isDeleted(i)) continue;
Document d = reader.document(i);
Document d2 = new Document();
for(Field f : (List<Field>)d.getFields()) {
Field f2 = f;
if(f.name().equals(FIELD_NAME))
f2 = new Field(FIELD_NAME, f.stringValue(), Field.Store.YES, Field.Index.NOT_ANALYZED);
d2.add(f2);
}
writer.addDocument(d2);
}
writer.optimize();
writer.close();

how to search a file with lucene

I want to do a search for a query within a file "fdictionary.txt" containing a list of words (230,000 words) written line by line. any suggestion why this code is not working?
The spell checking part is working and gives me the list of suggestions (I limited the length of the list to 1). what I want to do is to search that fdictionary and if the word is already in there, do not call spell checking. My Search function is not working. It does not give me error! Here is what I have implemented:
public class SpellCorrection {
public static File indexDir = new File("/../idxDir");
public static void main(String[] args) throws IOException, FileNotFoundException, CorruptIndexException, ParseException {
Directory directory = FSDirectory.open(indexDir);
SpellChecker spell = new SpellChecker(directory);
IndexWriterConfig config = new IndexWriterConfig(Version.LUCENE_20, null);
File dictionary = new File("/../fdictionary00.txt");
spell.indexDictionary(new PlainTextDictionary(dictionary), config, true);
String query = "red"; //kne, console
String correctedQuery = query; //kne, console
if (!search(directory, query)) {
String[] suggestions = spell.suggestSimilar(query, 1);
if (suggestions != null) {correctedQuery=suggestions[0];}
}
System.out.println("The Query was: "+query);
System.out.println("The Corrected Query is: "+correctedQuery);
}
public static boolean search(Directory directory, String queryTerm) throws FileNotFoundException, CorruptIndexException, IOException, ParseException {
boolean isIn = false;
IndexReader indexReader = IndexReader.open(directory);
IndexSearcher indexSearcher = new IndexSearcher(indexReader);
Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_20);
Term term = new Term(queryTerm);
Query termQuery = new TermQuery(term);
TopDocs hits = indexSearcher.search(termQuery, 100);
System.out.println(hits.totalHits);
if (hits.totalHits > 0) {
isIn = true;
}
return isIn;
}
}

where are you indexing the content from fdictionary00.txt?
You can search using IndexSearcher, only when you have index. If you are new to lucene, you might want to check some quick tutorials. (like http://lucenetutorial.com/lucene-in-5-minutes.html)

You never built the index.
You need to setup the index...
Directory directory = FSDirectory.open(indexDir);
Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_20);
IndexWriter writer = new IndexWriter(directory,analyzer,true,IndexWriter.MaxFieldLength.UNLIMITED );
You then need to create a document and add each term to the document as an analyzed field..
Document doc = new Document();
doc.Add(new Field("name", word , Field.Store.YES, Field.Index.ANALYZED));
Then add the document to the index
writer.AddDocument(doc);
writer.Optimize();
Now build the index and close the index writer.
writer.Commit();
writer.Close();

You could make your SpellChecker instance available in a service and use spellChecker.exist(word).
Be aware that the SpellChecker will not index words 2 characters or less. To get around this you can add them to the index after you have created it (add them into SpellChecker.F_WORD field).
If you want to add to your live index and make them available for exist(word) then you will need to add them to the SpellChecker.F_WORD field. Of course, because you're not adding to all the other fields such as gram/start/end etc then your word will not appear as a suggestion for other misspelled words.
In this case you'd have had to add the word into your file so when you re-create the index it would then be available as a suggestion. It would be great if the project made SpellChecker.createDocument(...) public/protected, rather than private, as this method accomplishes everything with adding words.
After all this your need to call spellChecker.setSpellIndex(directory).

Lucene Java opening too many files. Am I using IndexWriter properly?

My Lucene Java implementation is eating up too many files. I followed the instructions in the Lucene Wiki about too many open files, but that only helped slow the problem. Here is my code to add objects (PTicket) to the index:
//This gets called when the bean is instantiated
public void initializeIndex() {
analyzer = new WhitespaceAnalyzer(Version.LUCENE_32);
config = new IndexWriterConfig(Version.LUCENE_32, analyzer);
}
public void addAllToIndex(Collection<PTicket> records) {
IndexWriter indexWriter = null;
config = new IndexWriterConfig(Version.LUCENE_32, analyzer);
try{
indexWriter = new IndexWriter(directory, config);
for(PTicket record : records) {
Document doc = new Document();
StringBuffer documentText = new StringBuffer();
doc.add(new Field("_id", record.getIdAsString(), Field.Store.YES, Field.Index.ANALYZED));
doc.add(new Field("_type", record.getType(), Field.Store.YES, Field.Index.ANALYZED));
for(String key : record.getProps().keySet()) {
List<String> vals = record.getProps().get(key);
for(String val : vals) {
addToDocument(doc, key, val);
documentText.append(val).append(" ");
}
}
addToDocument(doc, DOC_TEXT, documentText.toString());
indexWriter.addDocument(doc);
}
indexWriter.optimize();
} catch (Exception e) {
e.printStackTrace();
} finally {
cleanup(indexWriter);
}
}
private void cleanup(IndexWriter iw) {
if(iw == null) {
return;
}
try{
iw.close();
} catch (IOException ioe) {
logger.error("Error trying to close index writer");
logger.error("{}", ioe.getClass().getName());
logger.error("{}", ioe.getMessage());
}
}
private void addToDocument(Document doc, String field, String value) {
doc.add(new Field(field, value, Field.Store.YES, Field.Index.ANALYZED));
}
EDIT TO ADD code for searching
public Set<Object> searchIndex(AthenaSearch search) {
try {
Query q = new QueryParser(Version.LUCENE_32, DOC_TEXT, analyzer).parse(query);
//search is actually instantiated in initialization. Lucene recommends this.
//IndexSearcher searcher = new IndexSearcher(directory, true);
TopDocs topDocs = searcher.search(q, numResults);
ScoreDoc[] hits = topDocs.scoreDocs;
for(int i=start;i<hits.length;++i) {
int docId = hits[i].doc;
Document d = searcher.doc(docId);
ids.add(d.get("_id"));
}
return ids;
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
This code is in a web application.
1) Is this the advised way to use IndexWriter (instantiating a new one on each add to index)?
2) I've read that raising ulimit will help, but that just seems like a band-aid that won't address the actual problem.
3) Could the problem lie with IndexSearcher?

1) Is this the advised way to use
IndexWriter (instantiating a new one
on each add to index)?
i advise No, there are constructors, which will check if exists or create a new writer, in the directory containing the index. problem 2 would be solved if you reuse the indexwriter.
EDIT:
Ok it seems in Lucene 3.2 the most but one constructors are deprecated,so the resue of Indexwriter can be achieved by using Enum IndexWriterConfig.OpenMode with value CREATE_OR_APPEND.
also, opening new writer and closing on each document add is not efficient,i suggest reuse, if you want to speed up indexing, set the setRamBufferSize default value is 16MB, so do it by trial and error method
from the docs:
Note that you can open an index with
create=true even while readers are
using the index. The old readers will
continue to search the "point in time"
snapshot they had opened, and won't
see the newly created index until they
re-open.
also reuse the IndexSearcher,i cannot see the code for searching, but Indexsearcher is threadsafe and can be used as Readonly as well
also i suggest you to use MergeFactor on writer, this is not necessary but will help on limiting the creation of inverted index files, do it by trial and error method

I think we'd need to see your search code to be sure, but I'd suspect that it is a problem with the index searcher. More specifically, make sure that your index reader is being properly closed when you've finished with it.
Good luck,

The scientific correct answer would be: You can't really tell by this fragment of code.
The more constructive answer would be:
You have to make sure that there is only one IndexWriter is writing to the index at any given time and you therefor need some mechanism to make sure of that. So my answer depends of what you want to accomplish:
do you want a deeper understanding of Lucene? or..
do you just want to build and use an index?
If you answer is the latter, you probably want to look at projects like Solr, which hides all the index reading and writing.

This question is probably a duplicate of
Too many open files Error on Lucene
I am repeating here my answer for that.
Use compound index to reduce file count. When this flag is set, lucene will write a segment as single .cfs file instead of multiple files. This will reduce the number of files significantly.
IndexWriter.setUseCompoundFile(true)