Here is one approach to use in a postfilter
1) In the collect() method call score for each doc. Use the scores to
create your scaleInfo.
2) Keep a bitset of the hits and a priorityQueue of your top X ScoreDocs.
3) Don't delegate any documents to lower collectors in the collect() method.
4) In the finish method create a score mapping (use the hppc
IntFloatOpenHashMap) with your top X docIds pointing to their score, using
the priorityQueue created in step 2. Then iterate the bitset (also created
in step 2) sending down each doc to the lower collectors, retrieving and
scaling the score from the score map. If the document is not in the score
map then send down 0.
You'll have setup a dummy scorer to feed to lower collectors. The
CollapsingQParserPlugin has an example of how to do this.
On Wed, Dec 11, 2013 at 2:05 PM, Peter Keegan <peterlkee...@gmail.com>wrote:
> Hi Joel,
>
> I thought about using a PostFilter, but the problem is that the 'scale'
> function must be done after all matching docs have been scored but before
> adding them to the PriorityQueue that sorts just the rows to be returned.
> Doing the 'scale' function wrapped in a 'query' is proving to be too slow
> when it visits every document in the index.
>
> In the Collector, I can see how to get the field values like this:
>
> indexSearcher.getSchema().getField("field(myfield").getType().getValueSource(SchemaField,
> QParser).getValues()
>
> But, 'getValueSource' needs a QParser, which isn't available.
> And I can't create a QParser without a SolrQueryRequest, which isn't
> available.
>
> Thanks,
> Peter
>
>
> On Wed, Dec 11, 2013 at 1:48 PM, Joel Bernstein <joels...@gmail.com>
> wrote:
>
> > Peter,
> >
> > It sounds like you could achieve what you want to do in a PostFilter
> rather
> > then extending the TopDocsCollector. Is there a reason why a PostFilter
> > won't work for you?
> >
> > Joel
> >
> >
> > On Tue, Dec 10, 2013 at 3:24 PM, Peter Keegan <peterlkee...@gmail.com
> > >wrote:
> >
> > > Quick question:
> > > In the context of a custom collector, how does one get the values of a
> > > field of type 'ExternalFileField'?
> > >
> > > Thanks,
> > > Peter
> > >
> > >
> > > On Tue, Dec 10, 2013 at 1:18 PM, Peter Keegan <peterlkee...@gmail.com
> > > >wrote:
> > >
> > > > Hi Joel,
> > > >
> > > > This is related to another thread on function query matching (
> > > >
> > >
> >
> http://lucene.472066.n3.nabble.com/Function-query-matching-td4099807.html#a4105513
> > > ).
> > > > The patch in SOLR-4465 will allow me to extend TopDocsCollector and
> > > perform
> > > > the 'scale' function on only the documents matching the main dismax
> > > query.
> > > > As you mention, it is a slightly intrusive design and requires that I
> > > > manage my own PriorityQueue (and a local duplicate of HitQueue), but
> > > should
> > > > work. I think a better design would hide the PQ from the plugin.
> > > >
> > > > Thanks,
> > > > Peter
> > > >
> > > >
> > > > On Sun, Dec 8, 2013 at 5:32 PM, Joel Bernstein <joels...@gmail.com>
> > > wrote:
> > > >
> > > >> Hi Peter,
> > > >>
> > > >> I've been meaning to revisit configurable ranking collectors, but I
> > > >> haven't
> > > >> yet had a chance. It's on the shortlist of things I'd like to tackle
> > > >> though.
> > > >>
> > > >>
> > > >>
> > > >> On Fri, Dec 6, 2013 at 4:17 PM, Peter Keegan <
> peterlkee...@gmail.com>
> > > >> wrote:
> > > >>
> > > >> > I looked at SOLR-4465 and SOLR-5045, where it appears that there
> is
> > a
> > > >> goal
> > > >> > to be able to do custom sorting and ranking in a PostFilter. So
> far,
> > > it
> > > >> > looks like only custom aggregation can be implemented in
> PostFilter
> > > >> (5045).
> > > >> > Custom sorting/ranking can be done in a pluggable collector
> (4465),
> > > but
> > > >> > this patch is no longer in dev.
> > > >> >
> > > >> > Is there any other dev. being done on adding custom sorting (after
> > > >> > collection) via a plugin?
> > > >> >
> > > >> > Thanks,
> > > >> > Peter
> > > >> >
> > > >>
> > > >>
> > > >>
> > > >> --
> > > >> Joel Bernstein
> > > >> Search Engineer at Heliosearch
> > > >>
> > > >
> > > >
> > >
> >
> >
> >
> > --
> > Joel Bernstein
> > Search Engineer at Heliosearch
> >
>
--
Joel Bernstein
Search Engineer at Heliosearch
