lucene-java-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Uwe Schindler" <...@thetaphi.de>
Subject RE: Document scoring order?
Date Thu, 04 Apr 2013 15:04:18 GMT
> Hi Otis,
> 
> It depends on the Scorer implementation.  The default iterates through
> matching documents by calling nextDoc(), which just moves along the
> postings lists in-order, but you could roll your own.  You're pretty constrained
> by the fact that the low-level DocIdSetIterators only move forward though.

Scorer extends DocIdSetIterator and is therefore required to work in docId order. The only
allowed exemption from this is Scorer.score(Collector) method, which *may* be out of order.
See my other mail.

> I'm experimenting with some out-of-order postings lists (for example, sorted
> by frequency) to allow early search termination for disjunction queries, but
> this has its own drawbacks - if postings lists for different terms are in
> different orders, then you can't use any Scorer that calls advance().
> 
> The other thing to look at would be sorted segments, see
> https://issues.apache.org/jira/browse/LUCENE-4752.
> 
> Alan Woodward
> www.flax.co.uk
> 
> 
> On 4 Apr 2013, at 02:56, Otis Gospodnetic wrote:
> 
> > Hi,
> >
> > When Lucene scores matching documents, what is the order in which
> > documents are processed/scored and can that be changed?  I'm guessing
> > it scores matches in whichever order they are stored in the index/on
> > disk, which means by increasing docIDs?
> >
> > I do see some out of order scoring is possible.... but can one visit
> > docs to score in, say, lexicographical order of a specific document
> > field?
> >
> > Thanks,
> > Otis
> > --
> > Solr & ElasticSearch Support
> > http://sematext.com/
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
> > For additional commands, e-mail: java-user-help@lucene.apache.org
> >



---------------------------------------------------------------------
To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
For additional commands, e-mail: java-user-help@lucene.apache.org


Mime
View raw message