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Subject: RE: Is it possible to get only one Field from a Document?
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Date: Wed, 11 Jun 2008 14:05:00 +0200
Message-ID: <50CA25BD6EEA954FA592C097399942E319B5327C@CM1.wis.local>
Thread-Topic: Is it possible to get only one Field from a Document?
thread-index: AcjLtnQdjIwmm2qoRVCIiDZP7DTk/AAAaInAAAC8N+A=
References: <484FB6EE.2050209@digitro.com.br>
 <50CA25BD6EEA954FA592C097399942E319B53279@CM1.wis.local>
From: "Daan de Wit" <d.de.wit@wis.nl>
To: <java-user@lucene.apache.org>

But I doubt this will solve your memory issue because nonstored fields =
are not read when retrieving the document.

-----Original Message-----
From: Daan de Wit [mailto:d.de.wit@wis.nl]=20
Sent: Wednesday, June 11, 2008 13:44
To: java-user@lucene.apache.org
Subject: RE: Is it possible to get only one Field from a Document?

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]=20
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=20
with Lucene, and each row has 25 columns. 20 cols have integer codes=20
used as filters (indexed/unstored), and the other 5 have (very) large=20
texts (also indexed/unstored). Currently the search I'm doing is like =
this:

Hits hits =3D searcher.search(query);
for (int i =3D 0; i < this.hits.length(); i++) {
    Document doc =3D this.hits.doc(i);
    String s =3D doc.get("fieldWanted");
     // does everything with the result, etc
}

We are trying to reduce memory usage, however. Is it possible to return=20
a Document object with just the Fields I really need? In the example,=20
each Document have 25 fields, and I just need one... would this=20
theoretically make any difference?


--=20

Marcelo Frantz Schneider
SIC - TCO - Tecnologia em Engenharia do Conhecimento
D=CDGITRO TECNOLOGIA
E-mail: marcelo.schneider@digitro.com.br
Site: www.digitro.com


--=20
Esta mensagem foi verificada pelo sistema de antiv=EDrus da D=EDgitro e
acredita-se estar livre de perigo.


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