Re: No future for DB2

"Mark Malakanov" <markmal_at_rogers.com> wrote in message news:Na2dnez77IBP62zfRVn-2Q_at_rogers.com...
> Madison Pruet wrote:
> > "Mark Malakanov" <markmal_at_rogers.com> wrote in message
> > news:xLydnbH1n-Pl8GzfRVn-tQ_at_rogers.com...
> >
> >>Madison Pruet wrote:
> >>
> >>>At a minimun the replication solution should be able to either prevent
> >>>triggers from firing on the target if it is populated by a replication
> >>>apply, with the assumption (and policing) that all of the tables
> >
> > associated
> >
> >>>with original transaction is replicated as part of that transaction.
> >>
> >>Yes, there is a function that should be called in an updateable MV
> >>target table trigger DBMS_MVIEW.I_AM_A_REFRESH. It returns FALSE if
> >>trigger is fired by local changes, and TRUE if trigger is fired by
> >>replication.
> >>
> >
> >
> > That's a good feature. But is there a way to prevent the trigger from
> > firing without having to make the trigger aware of the fact that
replication
> > exists? Otherwise, wouldn't it be difficult to use replication with
third
> > party applications?
> >
> >
> >
> I'm afraid it would be difficult. Triggers should be modified.

Mark - you are cross-posting to comp.databases.informix.

Believe me, I'm fully aware of how difficult this is, and also how important it is to make replication seemless for user and third-party applications.

IBM Informix Enterprise Replication supports the ability to dynamically fire or not fire the triggers based on wheither the update is performed by a user thread or by the replication apply. That means no modification of the trigger body is required to support replication, even though the tables have triggers defined. Informix Enterprise Replication also has the option to permit selective firing of the triggers. On some tables you might fire them; on others not.

Since by default, triggers are not fired on the targets, we are able to fairly easily configure the system to replicate all of the tables within the database without having to modify the triggers that are supporting the application. Or I can again fairly easily define a subset of tables within the database that I want to replicate as a group. Basically replicate all of the related tables affected by the firing of the triggers and not firing any triggers on the target. Received on Wed Aug 03 2005 - 21:52:57 CDT