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From Doug Cutting <cutt...@apache.org>
Subject Re: Queries with only non required terms: not as OR?
Date Wed, 03 Mar 2004 17:47:36 GMT
Paul Elschot wrote:
> I read a bit into the source code and I found this comment at 
> BooleanQuery.scorer():
> 
> // Also, at this point a
> // BooleanScorer cannot be embedded in a ConjunctionScorer, as the hits
> // from a BooleanScorer are not always sorted by document number (sigh)
> // and hence BooleanScorer cannot implement skipTo() correctly, which is
> // required by ConjunctionScorer.
> 
> The test function I used assumes that documents will be collected in 
> order. Could this be the source of the problem?

It could be.

I only realized recently that BooleanScorer does some local reordering 
of document numbers passed to the HitCollector.  There's no easy fix.

When I get a chance I intend to rewrite BooleanScorer to fix this and to 
correctly implement skipTo().  The result will be somewhat slower for 
some queries, especially those with a large number of optional terms, 
but will sometimes be faster when it's nested in other queries, and 
skipTo() can be leveraged.  I would like to get to this in next few 
weeks, and then make a 1.4 RC1 release.  The fix will take a few days 
work.  If I can find someone to fund the work it may happen sooner. 
Right now other projects have higher priority for me.

Doug


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