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From Shaun Senecal <ssenecal.w...@gmail.com>
Subject Re: PrefixQueries on large indexes (4M+ Documents) using a partial Query partial Filter solution
Date Thu, 15 Oct 2009 22:39:50 GMT
Ah!  I thought that the ConstantScoreQuery would also be rewritten into a
BooleanQuery, resulting in the same exception.  If that's the case, then
this should work.  I'll give that a try when I get into the office this
morning.


On Fri, Oct 16, 2009 at 6:46 AM, Michael McCandless <
lucene@mikemccandless.com> wrote:

> Well, you could wrap the C | D filter as a Query (using
> ConstantScoreQuery), and then add that as a SHOULD clause on your
> toplevel BooleanQuery?
>
> Mike
>
> On Thu, Oct 15, 2009 at 5:42 PM, Shaun Senecal <ssenecal.work@gmail.com>
> wrote:
> > At first I thought so, yes, but then I realised that the query I wanted
> to
> > execute was A | B | C | D and in reality I was executing (A | B) & (C |
> D).
> > I guess my unit tests were missing some cases and don't currently catch
> > this.
> >
> >
> >
> > On Thu, Oct 15, 2009 at 11:59 PM, Michael McCandless <
> > lucene@mikemccandless.com> wrote:
> >
> >> You should be able to do exactly what you were doing on 2.4, right?
> >> (By setting the rewrite method).
> >>
> >> Mike
> >>
> >> On Thu, Oct 15, 2009 at 8:30 AM, Shaun Senecal <ssenecal.work@gmail.com
> >
> >> wrote:
> >> > Thanks for the explanation Mike.  It looks like I have no choice but
> to
> >> move
> >> > any queries which throw TooManyClauses to be Filters. Sadly, this
> means a
> >> > max query time of 6s under load unless I can find a way to rewrite the
> >> query
> >> > to span a Query and a Filter.
> >> >
> >> >
> >> > Thanks again
> >> >
> >> >
> >> >
> >> > On Thu, Oct 15, 2009 at 6:52 PM, Michael McCandless <
> >> > lucene@mikemccandless.com> wrote:
> >> >
> >> >> On Thu, Oct 15, 2009 at 4:57 AM, Shaun Senecal <
> ssenecal.work@gmail.com
> >> >
> >> >> wrote:
> >> >>
> >> >> > Up to Lucene 2.4, this has been working out for us.  However,
in
> >> >> > Lucene 2.9 this breaks since rewrite() now returns a
> >> >> > ConstantScoreQuery.
> >> >>
> >> >> You can get back to the 2.4 behavior by calling
> >> >>
> prefixQuery.setRewriteMethod(prefixQuery.SCORING_BOOLEAN_QUERY_REWRITE)
> >> >> before calling rewrite().
> >> >>
> >> >> > Is there a way I can know that a ConstantScoreQuery will match
at
> >> >> > least 1 term (if not, I dont want to add it to the BooleanQuery)?
> >> >>
> >> >> There is a new method in 2.9: MultiTermQuery.getTotalNumberOfTerms(),
> >> >> which returns how many terms were visited during rewrite.  Would that
> >> >> work?
> >> >>
> >> >> > My understanding is that Lucene will apply the Filter (C | D)
> first,
> >> >> > limiting the result set, then apply the Query (A | B).  Is this
> >> >> > correct?
> >> >>
> >> >> Actually the filter & query clauses are AND'd in a sort of leapfrog
> >> >> fashion, taking turns skipping up to the other's doc ID and only
> >> >> accepting a doc ID when they both skip to the same point.  But this
> >> >> (the mechanics of how Lucene takes a filter into account) is an
> >> >> implementation detail and is likely to change.
> >> >>
> >> >> > If so, the end result is essentially the query: (A | B) &
(C | D)
> >> >>
> >> >> Except that C, D contribute no scoring information, if scoring
> >> >> matters.  If scoring doesn't matter, entirely (even for A, B), you
> >> >> should use a collector that does not call score() at all to save CPU.
> >> >>
> >> >> Mike
> >> >>
> >> >> ---------------------------------------------------------------------
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> >> >>
> >> >>
> >> >
> >>
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> >>
> >>
> >
>
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>

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