Slow performance on Hibernate + Java but fast when I use TOAD with the same native Oracle query

Question

I\'ve detected a performance problem with hibernate and native queries on Oracle. When I execute a complex SQL query with several parameters on TOAD I get the result in mili

Answer 1

I think what's happening with this code :

SQLQuery query = session.createSQLQuery("myNamedNativeQuery");
query.setParameter(nameParameter1, value1);
query.setParameter(nameParameter2, value2);
query.uniqueResult(); 

is this:

at line 1 : a query plan is created based on some expected values for your named parameters.

at line 4 : the query is executed with value1 and value2, but those values are not "good values" for the query plan that was elaborate at line 1 and so, the database is executing a very inappropriate plan for the actual values and it takes a lot of time.

Why ?

Looking at the source code of HibernateSessionImpl.createSQLQuery(...) I found this line of code:

SQLQueryImpl query = new SQLQueryImpl(
                sql,
                        this,
                        factory.getQueryPlanCache().getSQLParameterMetadata( sql )
        );

which is calling getQueryPlanCache() with some parameterMetaData. I assume that this metadata is not good enough.