[hibernate-issues] [Hibernate-JIRA] Created: (HSEARCH-194) Inconsistent performance between hibernate search and pure lucene access

[Stephane Nicoll (JIRA)]

Inconsistent performance between hibernate search and pure lucene access
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                 Key: HSEARCH-194
                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HSEARCH-194
             Project: Hibernate Search
          Issue Type: Bug
          Components: query
    Affects Versions: 3.0.1.GA
         Environment: Linux - Hibernate 3.2.6, Hibernate Annotations 3..3.1 - Lucene 2.3.1
            Reporter: Stephane Nicoll
            Priority: Critical
         Attachments: Monitor_Usage_Statistics.html

I have a simple index that contains:

* id (pk of the entity)
* keywords (a list of tokens)

The index contains 100.000 objects and the keywords field has 2 tokens from a list of 40 different values

What I want to do is retrieve all the IDs that matches a given lucene query on the keywords. So for that I'm doing something like:

FullTextSession fullTextSession = Search.createFullTextSession(session);
QueryParser parser = new QueryParser("keywords", luceneAnalyzer);
org.apache.lucene.search.Query hibernateQuery = parser.parse("foo AND bar");
FullTextQuery fullTextQuery = fullTextSession.createFullTextQuery(hibernateQuery, target);
fullTextQuery.setProjection("id");
fullTextQuery.setResultTransformer(resultTransformer);
Iterator it = fullTextQuery.iterate();

Where ResultTransformer is

private static class FirstObjectResultTransformer implements ResultTransformer {

        public Object transformTuple(Object[] objects, String[] strings) {
            return objects[0];
        }

        public List transformList(List list) {
            return list;
        }
    }

If I do a load test with a single thread, the execution time of my lucene query is around 200 msec. If I do a load test with 10 threads, the execution time is 2 sec (per user!). If I run the profiler on the service, I see lots of deadocks on SegmentReader.

Switching to a "non-shared" strategy removes the deadlocks but it's still slow (1.5 sec).

Now, If I execute the same query on the same index and the same host with only the lucene API, the query takes around 100msec with 10 concurrent users. I tried to use the lucene API from Hibernate Search but it did not change anything.

What am I missing? Attached the profiling result.



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