Hi Yang,
It would be legal for Lucene to perform such optimizations indeed.
On Tue, Sep 19, 2023 at 3:27 PM YouPeng Yang <yypvsxf19870...@gmail.com> wrote:
>
> Hi All
>
> Sorry to bother you.The happiest thing is studying the Lucene source
> codes,thank you for all the great works .
>
>
> About the BooleanQuery.I am encountered by a question about the execution
> of BooleanQuery:although,BooleanQuery#rewrite has done some works to remove
> duplicate FILTER,SHOULD clauses.however still the same term query can been
> executed the several times.
>
> I copied the test code in the TestBooleanQuery to confirm my assumption.
>
> Unit Test Code as follows:
>
>
>
> BooleanQuery.Builder qBuilder = new BooleanQuery.Builder();
>
> qBuilder = new BooleanQuery.Builder();
>
> qBuilder.add(new TermQuery(new Term("field", "b")), Occur.FILTER);
>
> qBuilder.add(new TermQuery(new Term("field", "a")), Occur.SHOULD);
>
> qBuilder.add(new TermQuery(new Term("field", "d")), Occur.SHOULD);
>
> BooleanQuery.Builder nestQuery = new BooleanQuery.Builder();
>
> nestQuery.add(new TermQuery(new Term("field", "b")), Occur.FILTER);
>
> nestQuery.add(new TermQuery(new Term("field", "a")), Occur.SHOULD);
>
> nestQuery.add(new TermQuery(new Term("field", "d")), Occur.SHOULD);
>
> qBuilder.add(nestQuery.build(),Occur.SHOULD);
>
> qBuilder.setMinimumNumberShouldMatch(1);
>
> BooleanQuery q = qBuilder.build();
>
> q = qBuilder.build();
>
> assertSameScoresWithoutFilters(searcher, q);
>
>
> In this test, the top boolean query(qBuilder) contains 4 clauses(3 simple
> term-query ,1 nested boolean query that contains the same 3 term-query).
>
> The underlying execution is that all the 6 term query were executed(see
> TermQuery.Termweight#getTermsEnum()).
>
> Apparently and theoretically, the executions can be merged to increase the
> time,right?.
>
>
> So,is it possible or necessary that Lucene merge the execution to optimize
> the query performance, even though I know the optimization may be difficult.
>
>
>
--
Adrien
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