nhibernate hydration performance

Context: Domain model of Documents having Editions and Tags.

What kind of figures are you going to expect when hydrating using nHibernate?

My domain model not very complex and when I query all Documents fetching Editions as well as Tags the query returns a little more than 8000 rows from the database - which in turn are hydrated into about 2300 Documents.

The database operation takes about 100ms and the hydration process takes 4000ms, which I find very strange.

dotTrace indicates a large number of calls (1.6M) to

"System.Data.SQLite.SQLite3.ColumnName(SQLiteStatement, Int3开发者_开发百科2)"

and the like.

The query is performed using Criteria like this:

var docsQuery = _session.CreateCriteria<Document>();            
docsQuery.SetFetchMode("Editions", FetchMode.Join);
docsQuery.SetFetchMode("Tags", FetchMode.Join);
docsQuery.SetResultTransformer(new DistinctRootEntityResultTransformer());
return docsQuery .List<Document>();

Note: Surely limiting the resultset will improve the performance. My primary concern was on why the bad hydration performance in general. Fiddling with session.FlushMode and session.CacheMode does not help a lot in my case.

UPDATE: Here is a screenshot from the profiler.

UPDATE 2: Checked the query times and they are about 100ms in all.

• Did you try a query without using DistinctRootEntityResultTransformer? (You may need to solve the N+1 problem, but there are solutions for that.)
• Have you turned on the reflection optimizer?