<vendor>
No.
WLS 6 (which is currently in beta) does indeed support 2PC (and EJB 2.0).
</vendor>
-- Rob
Rob Woollen
Sr Software Engineer
BEA WebLogic
[EMAIL PROTECTED]
On Thu, Nov 09, 2000 at 03:25:16PM -0800, Jonathan K. Weedon wrote:
> Rob,
>
> <vendor>
>
> And just to finish things off, you might point out that WebLogic
> Server does not currently support 2PC, so if you do have multiple
> resources you will have to use something else. Right?
>
> </vendor>
>
> -jkw
>
> Rob Woollen wrote:
> >
> > <vendor>
> >
> > I asked our JTA team for their answer on this one. Here's what they
> > said:
> >
> > In WebLogic Server our JDBC/RMI driver funnels database requests from
> > multiple servers over the same database connection. As long as only
> > one database is participating in the transaction, we don't incur any
> > two-phase commit overhead. Also, the database does not need to support
> > XA.
> >
> > In WebLogic Server 6.0 if the database does support XA, we can call
> > its JDBC driver directly from multiple servers. WebLogic's
> > transaction manager implements what's called a "one phase"
> > optimization: if there's only one XA resource participating in the
> > transaction, we don't run the two-phase commit protocol, and we don't
> > write a commit record to disk.
> >
> > </vendor>
> >
> > -- Rob
> >
> > Rob Woollen
> > Sr Software Engineer
> > BEA WebLogic
> > [EMAIL PROTECTED]
> >
> > On Thu, Nov 09, 2000 at 12:36:41PM -0600, Richard Monson-Haefel wrote:
> > > I stand corrected. Obviously, IAS has more sophisticated support for this
>scenario than other TMs.
> > >
> > > Thanks,
> > >
> > > Richard
> > >
> > > --
> > > Richard Monson-Haefel
> > > Author of Enterprise JavaBeans, 2nd Edition (O'Reilly 2000)
> > > Co-Author of Java Message Service (O'Reilly 2000)
> > > http://www.EjbNow.com
> > >
> > > "Jonathan K. Weedon" wrote:
> > >
> > > > Richard,
> > > >
> > > > Sorry, but you are wrong.
> > > >
> > > > It is possible to have two servers access a single database
> > > > in a single transaction. Two phase commit is not required for
> > > > this (as there is only a single resource), although XA is
> > > > required (so that the TM can determine that the two resources
> > > > are in fact the same, in that they have the same XA id).
> > > >
> > > > IAS 4.1.x provides such support out-of-the-box. That is, you
> > > > can have any number of EJBs access the same database from any
> > > > number of containers, all in a single transaction, and not
> > > > need 2PC.
> > > >
> > > > Many people don't realize this is possible because almost every
> > > > TM on the market does not support this optimization. For example,
> > > > neither Tuxedo nor Encina can pull off this trick.
> > > >
> > > > Of course, if you actually have two resources (that is, an Oracle
> > > > and a Sybase) both enlisted in the same transaction, then you
> > > > will need 2PC. And of course our product provides this capaibility
> > > > too, although it is more expensive due to the logging overhead
> > > > required to make the 2PC recoverable.
> > > >
> > > > -jkw
> > > >
> > > > Richard Monson-Haefel wrote:
> > > > >
> > > > > Although you are access the same database (resource) you will still need
>application servers that support two-phase commit (2PC) in order to execute operations
> > > > > across servers within a single transaction. The this is required because
>you are using two separate connections to the database that would otherwise be
>unaware of
> > > > > each other. You need to 2PC to inform the database that these two database
>connections are working together within the same transaction.
> > > > >
> > > > > It's feasible that a vendor could provide connection sharing through some
>type of database gateway -- that would eliminate the need for 2PC -- but I'm not
>aware of
> > > > > one that does this.
> > > > >
> > > > > Richard
> > > > > --
> > > > > Richard Monson-Haefel
> > > > > Author of Enterprise JavaBeans, 2nd Edition (O'Reilly 2000)
> > > > > Co-Author of Java Message Service (O'Reilly 2000)
> > > > > http://www.EjbNow.com
> > > > >
> > > > > "Maliyackel, Anup Kumar (CTS)" wrote:
> > > > >
> > > > > > hi
> > > > > >
> > > > > > I have read that when developinng J2ee applications using two app servers
>or
> > > > > > two databases, the two phase commit protocol is necessary to maintain data
> > > > > > consistency.
> > > > > >
> > > > > > If I am using two app servers , but writing to the same database how
> > > > > > important is this?
> > > > > >
> > > > > > Regards
> > > > > > Anup
> > > > > >
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