Hi.
I need to exclude duplicates in my database. The problem is that duplicates are not considered exact match but rather similar documents. For this purpose I decided to use FuzzyQuery like follows:

var fuzzyQuery = new global::Lucene.Net.Search.FuzzyQuery(
                     new Term("text", queryText),
                     0.8f,
                     0);
 hits = _searcher.Search(query);

The idea was to set the minimal similarity to 0.8 (that I think is high enough) so only similar documents will be found excluding those that are not sufficiently similar.

To test this code I decided to see if it finds already existing document. To the variable queryText was assigned a value that is stored in the index. The code from above found nothing, in other words it doesn't detect even exact match.

Index was build by this code:

 doc.Add(new global::Lucene.Net.Documents.Field(
            "text",
            text,
            global::Lucene.Net.Documents.Field.Store.YES,
            global::Lucene.Net.Documents.Field.Index.TOKENIZED,
            global::Lucene.Net.Documents.Field.TermVector.WITH_POSITIONS_OFFSETS));

I followed recomendations from bellow and the results are: TermQuery doesn't return any result. Query contructed with

 var _analyzer = new RussianAnalyzer();
 var parser = new global::Lucene.Net.QueryParsers
                .QueryParser("text", _analyzer);
 var query = parser.Parse(queryText);
 var _searcher = new IndexSearcher
       (Settings.General.Default.LuceneIndexDirectoryPath);
 var hits = _searcher.Search(query);

Returns several results with the maximum score the document that has exact match and other several documents that have similar content.