Re: Null scorer constructed by TermQuery

[Michael Kazekin <Mi...@mediainsight.info>]

Uwe,

I looked them up in Luke, these fields are present, are named the same, and
have proper values, so the problem seems to be somewhere else :((

But anyway, thanks for your help!

On 01/31/2012 12:50 PM, Uwe Schindler wrote:
> Hi,
>
> As this was originally a Solr index, are you sure, that the term is exactly
> in *that* spelling (including case) in the index? You should open the index
> with the Luke desktop tool and inspect the term index! Solr uses an analyzer
> when indexing or searching, so depending on the Solr config, it might be
> that the term is "normalized" or changed in any other way inside the index.
> TermQuery does not analyze, it looks up the raw term.
>
> Btw: SegmentReader.open(...) is wrong, must be IndexReader.open(), it just
> works because SR is a subclass and you can call static methods in
> subclasses.
>
> Uwe
>
> -----
> Uwe Schindler
> H.-H.-Meier-Allee 63, D-28213 Bremen
> http://www.thetaphi.de
> eMail: uwe@thetaphi.de
>
>> -----Original Message-----
>> From: Michael Kazekin [mailto:Michael.Kazekin@mediainsight.info]
>> Sent: Tuesday, January 31, 2012 9:30 AM
>> To: java-user@lucene.apache.org
>> Subject: Re: Null scorer constructed by TermQuery
>>
>> Uwe, thank you very much for such verbose answer!
>>
>> I tried the code you mentioned ( searcher.createNormalizedWeight(query) ),
>> but it doesn't work on Lucene 3.5 for me either :(
>>
>> My Solr server returns the document correctly on specified term (field and
>> value), field is indexed and stored.
>>
>> I'm really stuck on it, because the API code seems to be simple and has to
>> behave as expected, index exists, solr returns correct results.
>>
>> May be you have some thoughts on it, because my knowledge of "inner
> Lucene"
>> is not very good.
>>
>> My code is:
>>
>>           File file = new File(luceneDir);
>>
>>           Preconditions.checkArgument(file.isDirectory(), "Lucene
>> directory: " + file.getAbsolutePath() + " does not exist or is not a
> directory");
>>           Directory directory = FSDirectory.open(file); //index exists,
>>
>>           IndexReader reader = SegmentReader.open(directory, true);
>>
>>           IndexSearcher searcher = new IndexSearcher(reader);
>>
>>           TermQuery termQuery = new TermQuery(new Term("lang", "en"));
>>
>>
>>           Weight weight = searcher.createNormalizedWeight(termQuery);
>>
>>           Scorer scorer = weight.scorer(reader, true, false);
>>
>>           System.out.println("scorer = " + scorer); //outputs "scorer =
> null"
>>
>>
>> On 01/27/2012 08:46 PM, Uwe Schindler wrote:
>>> One addition:
>>>
>>> In general, your way how to get a scorer from a query is not supported
>>> (and does not work correct for all queries), the right way is *not* to
>>> use
>>> query.createWeight(searcher) but instead
>>> searcher.createNormalizedWeight(query).
>>>
>>> But that has nothing to do with the null scorer, which is a valid
>>> return value if the term does not exist and no docs can ever match.
>>>
>>>> You are creating a TermScorer on a composite (non atomic IndexReader
>>>> like SegmentReader). That's still supported in 3.x, but no longer
>>>> allowed in
>>> 4.0.
>>>> The backwards layer in 3.x had a bug before Lucene 3.5, so
>>>> theoretically
>>> your
>>>> code should work on 3.5:
>>>> https://issues.apache.org/jira/browse/LUCENE-3442
>>>>
>>>> But still: null is a valid return value for scorer()!!! It may return
>>> null, if no
>>>> document can  match this query. Means the term does not exist at all.
>>>>
>>>> Uwe
>>>>
>>>> -----
>>>> Uwe Schindler
>>>> H.-H.-Meier-Allee 63, D-28213 Bremen
>>>> http://www.thetaphi.de
>>>> eMail: uwe@thetaphi.de
>>>>
>>>>
>>>>> -----Original Message-----
>>>>> From: Michael Kazekin [mailto:Michael.Kazekin@mediainsight.info]
>>>>> Sent: Friday, January 27, 2012 4:39 PM
>>>>> To: java-user@lucene.apache.org
>>>>> Subject: Null scorer constructed by TermQuery
>>>>>
>>>>> Hi!
>>>>>
>>>>> I have a Solr-constructed index, which I read with this code:
>>>>>
>>>>> Directory directory = FSDirectory.open(file); IndexReader reader =
>>>>> IndexReader.open(directory, true); IndexSearcher searcher = new
>>>>> IndexSearcher(reader);
>>>>>
>>>>> I try to get a Scorer with this TermQuery ("lang" field is indexed
>>>>> and
>>>> stored and
>>>>> all data is available)
>>>>>
>>>>> TermQuery atomQuery = new TermQuery(new Term("lang", "ru"));
>>>>>
>>>>> Weight weight = atomQuery.createWeight(searcher); Scorer scorer =
>>>>> weight.scorer(reader, true, false);
>>>>>
>>>>>
>>>>>
>>>>> after this scorer is null.
>>>>>
>>>>>
>>>>>
>>>>> Does anyone know, what could be the problem here?
>>>>>
>>>>> I tried it with Solr. 3.4 and with Solr 3.5, results are the same.
>>>>>
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>>>
>>
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