Re: 9i streams vs triggers

servant wrote:

> Sybrand,
>
> I am having trouble understanding how I can design my database to have data
> that is updated and selected simultaneously without contention. The update
> will lock the row and block the select and vice versa, right? Can you
> expand . . .?
>
> What I meant by replication is logical hot standby so I think we agree
> there. That solves the contention issue but does not address the complexity
> issue. I agree that this is not a pretty solution, but I need a way to take
> the data from one data model, massage it with existing code (so I don't have
> to develop/maintain it in two places), and write it to another "reporting"
> database at near real time. Those requirements don't leave me with any
> pretty solutions that I can think of. I am no guru, though, so I certainly
> welcome any suggestions.
>
> RAC, as I understand it, will give me scalability which, again, solves the
> performance/contention issue but does not address the complexity issue.
>
> You mentioned "Advanced Replication". I need to find out what that is (I am
> new to Oracle but learning fast). If it can call Java methods it just might
> work. Can you offer opinions on this versus triggers or streams?
>
> I'm off to tahiti (.oracle.com) . . .
>
> "Sybrand Bakker" <gooiditweg_at_nospam.demon.nl> wrote in message
> news:77pr1v42q0kef48ad29cacqjvsinbqp6vl_at_4ax.com...
> > On Thu, 9 Jan 2003 13:06:43 -0600, "servant" <mjohns1_at_uhc.com> wrote:
> >
> > >I have been tasked with developing a reporting architecture for an
> > >application that has been developed over the last few months. I have
> been
> > >told there are 2 main concerns: performance (contention) and complexity
> of
> > >the data model. I am thinking of using Oracle's replication to maintain
> a
> > >(near) real-time replica. That (basically) resolves the contention
> issue.
> > >The complexity issue is more difficult.
> > >
> > >I am thinking about using 1) streams against the redo logs or 2) triggers
> to
> > >pull the data from the replica, apply business logic to it, and populate
> a
> > >"logical" data model on which reports can be generated. I would like to
> use
> > >the same abstraction layer to go from the physical to the logical data
> model
> > >as the application interface uses (Java objects with EJBs). In other
> words,
> > >I need the code inside the streams or triggers to call Java methods (ie:
> > >loadCustomerData(cust_id)) which would get the data and apply any
> business
> > >logic and then populate the "logical" database.
> > >
> > >In essence, I think I am being asked to create a data warehouse, but I
> > >haven't convinced myself of that yet.
> > >
> > >Anyway, here is my question: Does anyone have an opinion on which method
> > >(streams or triggers) would tax my replica database more--from a CPU,
> > >network, and/or contention perspective? Any opinions from other
> > >perspectives which option is better (maintenance, etc).
> > >
> > >
> >
> > First of all I would like to question the need of a replica database
> > for reporting purposes. As for contention, this is simply not an
> > issue, if the application has been designed properly. Your post has a
> > distinct smell of finding a 'hardware solution' read 'workaround' for
> > what is in reality a software design problem.
> > If you really think you need a hardware solution you could just as
> > well consider RAC, to have multiple servers running on the same
> > instance.
> > As for your option 1) you seem to be trying to re-invent the standby
> > database technology . One simple advice: don't. You would never get it
> > work, and provided your organisation has still a bag of $$ floating
> > arond: get Oracle Enterprise Edition, set up a standby database which
> > will use the redolog to keep the standby database up-to-date and start
> > living
> > As for your option 2) this seems like yet another solution which is
> > going to be designed in a bike-shed. Replication can be accomplished
> > by setting up the Advanced Replication option, and designing
> > 'home-grown' solutions will definitely make you bald sooner and cost
> > more.
> >
> > Regards
> >
> >
> > Sybrand Bakker, Senior Oracle DBA
> >
> > To reply remove -verwijderdit from my e-mail address

Forgot to mention this in my previous post:

Go to http://tahiti.oracle.com and search under the topic "MULTIVERSIONING."

Daniel Morgan Received on Fri Jan 10 2003 - 10:52:39 CST