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From Yang <teddyyyy...@gmail.com>
Subject Re: Number of Boolean Clauses (AND vs OR)
Date Fri, 15 Apr 2011 18:00:06 GMT
sorry, please ignore this post ..... it was an old one from nabble.com

On Mon, Apr 11, 2011 at 6:13 PM, yangyangyyy <teddyyyy123@gmail.com> wrote:
> Thanks Doug:
>
> when you say "executed" in parallel, could you please elaborate more on what
> "execute" refers to?
>
> I just managed to look through the code. on our Solr setup, by default, a
> query "dog cat" (not phrase search) comes to a DisjunctionSumScorer, and if
> by "execute" you mean the call to score(), it seems that the
> DisjunctionSumScorer still evaluates score() serially, just iterating down
> the multiple subscorers queue
> "scorerDocQueue", as is in
>
> DisjunctionSumScorer:
>
>  protected boolean advanceAfterCurrent() throws IOException {
>
>
>
> ConjunctionScorer looks similar , just different in the way doNext()
> iterates through the doc queues.
>
> if the above scenario is indeed run in serial, how could we enable parallel
> evaluation? does that need some special config? (this is lucene 2.9.4 + Solr
> 1.4.2 )
>
> Thanks a lot
> Yang
>
>
> ###############################
> On 04/11/2011 01:25 PM, entdeveloper wrote:
>> Thanks Otis. And by your answer, does this mean that individual clauses in
>> a
>> boolean query are executed sequentially? not in parallel?
>
> Clauses are executed in parallel.  The execution of a conjunction is
> able to efficiently skip occurrences in ranges of documents that do not
> contain all clauses, while, for a disjunction, every occurrence of every
> clause must be considered.
>
> Doug
>
> --
> View this message in context: http://lucene.472066.n3.nabble.com/Number-of-Boolean-Clauses-AND-vs-OR-tp2807905p2809558.html
> Sent from the Lucene - General mailing list archive at Nabble.com.
>

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