Dirty reads without changing transaction isloation?

chubbard · **Posted:** Mon Apr 02, 2007 3:07 pm

I have a legacy database that I'm mapping with hibernate, and my DBAs are asking if I can make my hibernate statements use dirty reads. I know all of the issues this brings up, and I know it's not safe. And, I've been through all of those discussions with my DBAs and they're not statisfied. I know I can turn down my transaction isloation level from read committed to read uncommited, but I was wondering if there is a way to provide locking hints in certain cases to request dirty reads from a higher transaction isloation level?

Thanks
Charlie

christian · **Posted:** Mon Apr 02, 2007 3:34 pm

You can only change the whole default connection isolation to read uncommitted, not for individual statements. Let me guess, IBM DB2? Fire these guys before they do more damage to your company. I'm serious.

christian · **Posted:** Mon Apr 02, 2007 3:36 pm

Oh, forgot the DB2 trick for "performance": Implement org.hibernate.Interceptor.onPrepareStatement() and append "WITH UR" or whatever your "DBA" tells you.

chubbard · **Posted:** Mon Apr 02, 2007 3:54 pm

Actually it's MS SQL Server. :-( They add the "NO LOCK" hint on the SQL statements instead of the "WITH UR" to get dirty reads. So by creating an Interceptor I could add the lock hint if I so wished. Ok good to know. Not sure if I'll have to do it, but good to know.

Thanks
Charlie