Re: TAF and FCF together ?

DA Morgan wrote:
> joeNOSPAM_at_BEA.com wrote:
> > Hi, and thank you very much. I'm looking over the download
> > now. It doesn't seem to do any serious queries. It only does
> > one tiny "select count(*) from ..." which will only return a
> > single one-row, one-column result set. This would never test
> > or expose the program to any TAF repositioned cursors. I
> > would suggest returning (and checking!) a significant data set,
> > at least 500 rows. I would make sure the count of rows is always
> > verifiable, and I would make the program update the data so
> > that if a query had to be rerun under-the-covers the order of the
> > data might change change. Also this example doesn't do any
> > transactions. If someone fluent with hacking that package would
> > like to contact me about suggestions for making it attempt
> > something more business-like, I would happily help/consult.
> >
> > Joe Weinstein at BEA Systems
>
> Joe you've been here at c.d.o.s. long enough you know we vigorously
> discourage top posting. Please adhere to the standard. Thanks.
>
> With a TAF failover the query restarts with the same SCN. Thus the
> result set is exactly the same.
> --
> Daniel Morgan
> University of Washington
> Puget Sound Oracle Users Group

Sorry, my newsreader sometimes makes it very difficult to bottom post!

My concern is that the SCN does not necessarily indicate the same DBMS datum from DBMS to DBMS over time, for instance if the table has changed between the failure of a connection and a eventual reconnect to the other DBMS. The oracle TAF document warns that on occasion, a query will fail, and I was interested in expanding the example to actually exercise TAF's requery ability, and wondering if these failures are always obvious.

   I think we both agree that TAF is being deprecated, but there are some, obviously that are still being lured by the siren-call of it's promise. If we expanded the example to more thoroughly test TAF, and if it exposed more of the Oracle-documented problems, it might serve to sway these tempted souls from the rocks or show how to handle them.

Joe Received on Fri Sep 15 2006 - 17:57:28 CDT