I have a number of things to say here:
(1) this recommendation seems to be usually made by DBAs who have a lot of experience with batch processing and don't think about the fact that online applications use VERY short transactions, and usually aren't running queries that lock up huge numbers of rows. Remember, in read committed isolation level, locks held by SELECTs are momentary locks only.
(2) dirty reads are very dangerous, especially if you have a second-level cache .. NEVER use "with ur" for a query that could put data in the second-level or query caches.
(3) why not just set the JDBC isolation level if you absolutely insist that you need read uncommitted isolation.
Now, I am most certainly NOT a DBA, but I have come into contact with this on a couple of customer sites and, after talking stuff through withthe DBAs, it turned out that uncommitted read was probably not appropriate for the Hibernate application.
What do you think?
|