Discovered a useful openjpa property... On 9/25/07, Kevin Sutter <[EMAIL PROTECTED]> wrote: > > Hi, > I'm trying to figure out the ins and outs of Section 3 Object Locking as > they relate to running OpenJPA within an application server > (container-managed) environment such as WebSphere. It seems that several of > these properties and/or API's are assuming an application-managed > environment outside of a container. Either that, or there are implied > behaviors of the container environment that WebSphere is not providing. > > For example, the ReadLockLevel property allows for none, read, or write > values. What does it mean for "none" in an application server environment? > If the Container has already initiated a global (JTA) transaction, when > OpenJPA requests a Connection (via the <jta-data-source> element), this > Connection is automatically enlisted in the Transaction. Thus, when the > "Select..." statement is issued, we will get a Read Lock on the row with the > default isolation level setting (supposed to be Read Committed). So, how is > OpenJPA supposed to honor the "none" ReadLockLevel request? > > Several places in this section of the document, there are references to > optimistic and non-optimistic (pessimistic) transactions. Not lock > managers, but transactions. The OpenJPA manual indicates that it can > support optimistic transactions by not issuing the database transaction > until flush or commit time. But, I don't see how we are can configure for > the use of optimistic vs pessimistic transactions. It looks like the > EntityTransaction interface is optimistic by default. But, is there anyway > to control the optimisticity (new word) of a global transaction? The answer > to these questions actually help with the first example outlined above.
Okay. It was pointed out to me that the openjpa.Optimistic property exists to indicate whether to use optimistic or non-optimistic transaction semantics. So, it's not just an implicit operation. But, I guess my question still exists on how this applies to container managed JTA transactions. I will continue to investigate, but if there are any existing experts in this area, I'd appreciate some insights. :-) Thanks! Many other similar questions are in my mind, but let's start with these > since I think these will give a basis for the rest of the discussion. > > Thanks, > Kevin >
