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From Grant Ingersoll <grant.ingers...@gmail.com>
Subject Re: regarding FieldSelector
Date Fri, 14 Sep 2007 13:39:17 GMT
Searcher is a Searchable and Searchable defines the doc() method with  
FieldSelector, but I suppose we could add an abstract declaration of  
it to Searcher, since it has to be implemented on all derived   
classes anyway due to it being on the Searchable interface.

So, you can either cast to a known Searcher or I suppose you can  
figure out a way to get the IndexReader.  What kind of Searcher are  
you using?

-Grant

On Sep 13, 2007, at 4:50 AM, Mohammad Norouzi wrote:

> Thanks
> as I saw the documents, we can only use this great field selector in
> IndexReader.document() method the problem is I have a Searcher in  
> my result
> set structure and when the client calls getString("a_field_name")  
> at that
> time I invoke the searcher.doc(current_doc_id).get("a_field_name),
> I already collected the result IDs. so in my case, I can't use
> FieldSelector.
>
> Do I have to revise the way of retrieving documents in my code?
>
>
>
> On 9/12/07, Erick Erickson <erickerickson@gmail.com> wrote:
>>
>> Well, it depends on what "improve the search process" means
>> in your context <G>..
>>
>> But I had a case similar to yours that I wrote up in the Wiki where
>> my search times improved about 10X by using lazy loading. You
>> might want to read that entry here...
>>
>> http://wiki.apache.org/lucene-java/FieldSelectorPerformance
>>
>> Note the peculiar characteristics of my data set, I really suspect
>> that a 10x improvement in retrieval speed is atypical...
>>
>> As for when lazily-loaded fields actually get loaded, I didn't really
>> have to explore it very fully, but a short experiment should do it
>> for you.....
>>
>> Best
>> Erick
>>
>> On 9/12/07, Mohammad Norouzi <mnrz57@gmail.com> wrote:
>>>
>>> Hi Grant,
>>> Really thanks for your nice document about advanced Lucene. it  
>>> was very
>>> useful for me.
>>>
>>> as I understand, we can set some large fields to be lazily  
>>> loading, now
>> my
>>> question is when it will be loaded? it make sense when we call
>>> doc.get("field_name")
>>> it will load from the index, Am I right?
>>>
>>> in my application, I've provided a result set structure to navigate
>>> between
>>> results and documents and provide a get(String fieldname) method  
>>> just
>> like
>>> java.sql.ResultSet.getString() method, and also this result set
>> implements
>>> HitCollector in order to collect my own ID rather than Lucene's  
>>> document
>>> id,
>>> so I think I can set my field ID to be loaded always and the other
>> fields
>>> to
>>> be lazily loading, Does this improve the search process?
>>>
>>> again, thank you very much indeed.
>>>
>>>
>>> On 9/12/07, Grant Ingersoll <gsingers@apache.org> wrote:
>>>>
>>>> Hi Mohammad,
>>>>
>>>> The typical use cases are:
>>>> 1. You have several small fields used in a results display and  
>>>> one or
>>>> two large fields (i.e. the original document) and you don't want to
>>>> pay the cost of loading the large fields for results display  
>>>> because
>>>> most of them won't be chosen.  When a result is chosen, the lazily
>>>> loaded field will be retrieved.
>>>>
>>>> 2. You only want to load certain fields, or the first field, or you
>>>> just want to know the size of a field.
>>>>
>>>> Basically, it gives you control over how fields are loaded from  
>>>> disk
>>>> in Lucene.
>>>>
>>>> See my ApacheCon Europe presentation http://cnlp.org/presentations/
>>>> slides/AdvancedLuceneEU.pdf for a few slides (towards the end) on
>>>> FieldSelector.
>>>>
>>>> On Sep 12, 2007, at 5:13 AM, Mohammad Norouzi wrote:
>>>>
>>>>> Hi all,
>>>>>
>>>>> Can anyone explain what is the FieldSelector and the usage or
>>>>> benefits of
>>>>> this structure? I read the javadocs but I can't get for what goal
>>>>> it is
>>>>> provided in Lucene.
>>>>>
>>>>> Thanks in advance
>>>>>
>>>>> --
>>>>> Regards,
>>>>> Mohammad
>>>>> --------------------------
>>>>> see my blog: http://brainable.blogspot.com/
>>>>> another in Persian: http://fekre-motefavet.blogspot.com/
>>>>
>>>> --------------------------
>>>> Grant Ingersoll
>>>> http://lucene.grantingersoll.com
>>>>
>>>> Lucene Helpful Hints:
>>>> http://wiki.apache.org/lucene-java/BasicsOfPerformance
>>>> http://wiki.apache.org/lucene-java/LuceneFAQ
>>>>
>>>>
>>>>
>>>> ------------------------------------------------------------------- 
>>>> --
>>>> To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
>>>> For additional commands, e-mail: java-user-help@lucene.apache.org
>>>>
>>>>
>>>
>>>
>>> --
>>> Regards,
>>> Mohammad
>>> --------------------------
>>> see my blog: http://brainable.blogspot.com/
>>> another in Persian: http://fekre-motefavet.blogspot.com/
>>>
>>
>
>
>
> -- 
> Regards,
> Mohammad
> --------------------------
> see my blog: http://brainable.blogspot.com/
> another in Persian: http://fekre-motefavet.blogspot.com/

------------------------------------------------------
Grant Ingersoll
http://www.grantingersoll.com/
http://lucene.grantingersoll.com
http://www.paperoftheweek.com/



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