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From Alex <chy101...@hotmail.com>
Subject RE: Is it possible to get only one Field from a Document?
Date Wed, 11 Jun 2008 14:41:55 GMT
if you have many terms across the fields, you might want to invoke
IndexReader's setTermInfosIndexDivisor() method, which would
reduce the in memory term infos used to lookup idf, but a (slightly)
slower search.




> From: gsingers@apache.org
> To: java-user@lucene.apache.org
> Subject: Re: Is it possible to get only one Field from a Document?
> Date: Wed, 11 Jun 2008 08:22:22 -0400
> 
> For the record, Hits.id(int i) returns the document number.  Note,  
> though, that Hits is now deprecated, as pointed out by the link to  
> 1290, so going the TopDocs route is probably better anyway.
> 
> -Grant
> 
> On Jun 11, 2008, at 7:43 AM, Daan de Wit wrote:
> 
> > This is possible, you need to provider a FieldSelector to  
> > IndexReader#document(docId, selector). This won't work with Hits  
> > though, because Hits does not expose the document number, so you  
> > need to roll your own solution using TopDocs or HitCollector, for  
> > information see the discussion in this issue: https://issues.apache.org/jira/browse/LUCENE-1290
> >
> > Kind regards,
> > Daan de Wit
> >
> > -----Original Message-----
> > From: Marcelo Schneider [mailto:marcelo.schneider@digitro.com.br]
> > Sent: Wednesday, June 11, 2008 13:29
> > To: java-user@lucene.apache.org
> > Subject: Is it possible to get only one Field from a Document?
> >
> > I have a environment where we have indexed a DB with about 6mil  
> > entries
> > with Lucene, and each row has 25 columns. 20 cols have integer codes
> > used as filters (indexed/unstored), and the other 5 have (very) large
> > texts (also indexed/unstored). Currently the search I'm doing is  
> > like this:
> >
> > Hits hits = searcher.search(query);
> > for (int i = 0; i < this.hits.length(); i++) {
> >    Document doc = this.hits.doc(i);
> >    String s = doc.get("fieldWanted");
> >     // does everything with the result, etc
> > }
> >
> > We are trying to reduce memory usage, however. Is it possible to  
> > return
> > a Document object with just the Fields I really need? In the example,
> > each Document have 25 fields, and I just need one... would this
> > theoretically make any difference?
> >
> >
> >
> >
> > -- 
> >
> > Marcelo Frantz Schneider
> > SIC - TCO - Tecnologia em Engenharia do Conhecimento
> > DÍGITRO TECNOLOGIA
> > E-mail: marcelo.schneider@digitro.com.br
> > Site: www.digitro.com
> >
> >
> > -- 
> > Esta mensagem foi verificada pelo sistema de antivírus da Dígitro e
> > acredita-se estar livre de perigo.
> >
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
> > For additional commands, e-mail: java-user-help@lucene.apache.org
> >
> >
> > ---------------------------------------------------------------------
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> >
> 
> --------------------------
> Grant Ingersoll
> http://www.lucidimagination.com
> 
> Lucene Helpful Hints:
> http://wiki.apache.org/lucene-java/BasicsOfPerformance
> http://wiki.apache.org/lucene-java/LuceneFAQ
> 
> 
> 
> 
> 
> 
> 
> 
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