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

Inconsistent performance between hibernate search and pure lucene access ------------------------------------------------------------------------ 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 Fix For: 3.1.0.Beta1 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.