Hi

I'm currently facing a big performace problem with my web app using NHibernate. The source of the problem is "search" functionality, when search results are bigger (e.g. 1000 rows or more).
I discovered with sql server profiler that the most of the time takes the bunch of "UPDATE" commands executed with every single record within the result set. It is only a time-waster because I do not alter any of those objects.

My current workaround is to avoid session flushing in those cases , but it is not enough - I need session flushing for example to store some preferences etc. on the search page.

Can anybody tell me why not-even-touched objects perform those annoying UPDATEs? And how to avoid this? :shock:

Your data probably doesn't quite match the property definition - so whan class is loaded some properties are detected as dirty and are updated.
If you have log4net configured - look in logs for something like:
"Persister.AbstractEntityPersister - YourClass.Property is dirty".
Happens often with Nullable columns that can't be Nulls in native VS datatypes (dates, integers, etc).

Yes, you are right. I was using standard Date type to store nulls ( setting it to DateTime.MinValue puts NULL into database). Just found that as a simpler alternative to Nullables.

Now I have to replace all such cases with the NullableDateTime , I checked - it fixes my "updates" problem.

Thanks for help.