Re: (Java) Synchronizing multiple app servers through Oracle

On Dec 22 2007, 6:36 am, Galen Boyer <galen_bo..._at_yahoo.com> wrote:
> On Fri, 14 Dec 2007, shortcut..._at_googlemail.com wrote:
> > On Dec 13, 11:13 pm, chrism..._at_gmail.com wrote:
> >> On Dec 13, 4:07 am, Robert Klemme <shortcut..._at_googlemail.com> wrote:
>
> >> > On Dec 13, 2:10 am, chrism..._at_gmail.com wrote:
>
> >> > > What is the recommended way for using an Oracle database to
> >> > > synchronize multiple app servers? When I speak of synchronizing,
> >> > > I'm referring to the Java use of the word, where you can lock a
> >> > > section of code so other threads don't access that section at the
> >> > > same time.
>
> You do that because the code has values that can change for the entire
> JVM's instantiated objects, correct? Why do you think you need to do
> that with the database?
>
> --
> Galen Boyer

OK. What I'm trying to do is have N number of Java-based app servers use the database as a way of synchronizing between each other. Perhaps the more typical way of doing this is opening up sockets on each app server and broadcasting information between all the servers to the let them all know what everyone else is doing. I was hoping I could more easily accomplish the same thing using the built-in functionality of the database, because all the app servers need to access the database anyway.

Here's what I'm doing:
I have a table which contains records to process. Each app server can process these records. However, it is important that no 2 (or more) app servers attempt to process the same records. So what I'm doing is making a call to dbms_lock() to ensure that when I'm picking out records to process, no other app server is doing the same thing. After I pick the records, I move them to another table, then I release the lock with dbms_lock().

If there is a better way to achieve the same thing through the database, I'd love to hear it.

Thanks. Received on Mon Jan 21 2008 - 12:51:34 CST