NHibernate: a little trick when working with Oracle or PostgreSQL
The ADO.NET providers for Oracle , PostgreSQL, and perhaps others have one unpleasant feature that can affect the performance of your application if you request large amounts of data from the server: they do not cache IDataReader.GetOrdinal method calls. As it turned out, this is very critical for NHibernate , but, fortunately, the developers of NHibernate (or rather Hibernate ) have noticed this problem and have already solved it.
But this feature went unnoticed and almost not documented.
In order for NHibernate to enable the caching of IDataReader.GetOrdinal calls, it is necessary to set the “adonet.wrap_result_sets” option to “true” in hibernate.cfg:
')
Using FluentNHibernate, this is done like this:
The _ExposeConfiguration_ method adds the actions that will be invoked on the NHibernate.Cfg.Configuration object when the BuildConfiguration method is called . Thus, the code above will be similar to the following:
But this feature went unnoticed and almost not documented.
In order for NHibernate to enable the caching of IDataReader.GetOrdinal calls, it is necessary to set the “adonet.wrap_result_sets” option to “true” in hibernate.cfg:
<?xml version="1.0" encoding="utf-8" ?> <hibernate-configuration xmlns="urn:nhibernate-configuration-2.2"> <!-- other options --> <session-factory name="MySessionFactory"> <!-- other session factory options --> <property name="adonet.wrap_result_sets">true</property> </session-factory> </hibernate-configuration> ')
Using FluentNHibernate, this is done like this:
var config = Fluently.Configure() .ExposeConfiguration(c => c.SetProperty(Environment.WrapResultSets, "true")) .Database(db) /* other configuration */ .BuildConfiguration(); The _ExposeConfiguration_ method adds the actions that will be invoked on the NHibernate.Cfg.Configuration object when the BuildConfiguration method is called . Thus, the code above will be similar to the following:
var config = Fluently.Configure() .Database(db) /* other configuration */ .BuildConfiguration(); config.SetProperty(NHibernate.Cfg.Environment.WrapResultSets, "true"); Related Links
Source: https://habr.com/ru/post/147450/
All Articles