Re: Intersecting a precalculated OpenBitSet with results

[Chris Hostetter <ho...@fucit.org>]

: We currently are intersecting a precalculated OpenBitSet (that does not
: affect score) with search by adding it to the filters in the ResponseBuilder
: via a wrapped in a ConstantScoreQuery and Filter.  We do this just before
: QueryComponent does its job.   

	...

: But, it does more work than needed.  Wouldn't it be better to just intersect
: this set with the results after they are determined?  To do this, Query
: Component needs a place to allow intersections before it stuffs the response
: in the response.  

I think a simpler approach might be to write a component that runs after 
QueryComponent which:
 * extracts the doclist/set currently in the response (by QueryComponent)
 * intersects them with the computed bitsets
 * writes the new doclist/docset back into the response


However: i wouldn't actaully assume that's better then your current 
approach of wrapping the OpenBitSet into a ConstantScoreQuery -- your 
current approach is probably helping the the IndexSearcher "skip" past a 
lot of docs w/o scoring them, but applying the intersection after the fact 
would eliminate that optimization.

It's also very hard to compute a DocList from an intersection after the 
fact ... you essentially need to re-execute the search anyway since it 
only keeps track of a set number of sorted documents.




-Hoss