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From Kumaran Ramasubramanian <kums....@gmail.com>
Subject Re: Difference in Retrieving values of a docvalue field using atomicreader over duplicate StoredField
Date Fri, 03 Jun 2016 14:20:14 GMT
Thanks a lot for the clarification mike :-)



--
*​*​
Kumaran R




On Thu, Jun 2, 2016 at 2:38 AM, Michael McCandless <
lucene@mikemccandless.com> wrote:

> Well, each access may involve disk seeks (if the pages are not already hot
> in the OS's IO cache).
>
> So if you do some doc values + some stored fields you're looking at
> multiple seeks per docID you retrieve.
>
> Really you should only do this for a few hits, e.g. one page worth.
>
> Mike McCandless
>
> http://blog.mikemccandless.com
>
> On Wed, Jun 1, 2016 at 3:15 PM, Kumaran Ramasubramanian <
> kums.134@gmail.com>
> wrote:
>
> > Hi All,
> >
> >
> > In javadoc of every docvalue field
> > <
> >
> https://lucene.apache.org/core/4_10_4/core/org/apache/lucene/document/SortedNumericDocValuesField.html
> > >,
> > there is line like
> >
> > ​
> > > If you also need to store the value, you should add a separate
> > StoredField
> > > <
> >
> https://lucene.apache.org/core/4_10_4/core/org/apache/lucene/document/StoredField.html
> > >
> > >  instance.​
> >
> >
> >
> >
> https://lucene.apache.org/core/4_10_4/core/org/apache/lucene/document/SortedNumericDocValuesField.html
> >
> >
> >
> >
> > But, we are able to retrieve the value of SortedNumericDocValuesField
> > using AtomicReader also
> >
> > for (AtomicReaderContext context : indexReader.leaves())
> > > {
> > >  AtomicReader atomicReader = context.reader();
> > >  SortedNumericDocValues
> > >  sortedDocValues=DocValues.getSortedNumeric(atomicReader, "Numeric
> > > ​_docvalue​
> > > _price");
> > > }
> >
> >
> > ​So what is the difference actually? Is there any performance or time
> taken
> > issue in retrieving values of a docvalue field using atomicreader over
> > StoredField? ​
> >
> > Please clarify me what am i missing?​
> >
> > Thanks in advance
> >
> >
> > ​--​
> >
> > Kumaran R
> >
>

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