Mailing List Archive

Hi All

During my unemployment time ,the happiest thing is diving to study the
Lucene Source Code ,thanks for all the work .

About the BooleanQuery.I am encounterd 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 copy the test code in the TestBooleanQuery to approve 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-quey).

The underlying execution is that the 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 there any possible or necessary that Lucene merge the execution to
optimize the query performance, even I know the optimization may be
difficult.