Re: TAF and FCF together ?

Hi Joe,

These are very good questions that anyone contemplating TAF should investigate..
I have discussed some of these in my book (chapter 7) and fairness towards those who bought it suggests that i only give the following summary:
a) things that TAF does well (transparently): connection failover and query resubmit (or query failover) - with performance penalty b) things that TAF does not do well (not transparent or does not work at all): rolling back active transaction, and failing over session states

As of 10g R2, FCF is bound to RAC while TAF may be used to failover single-instance sites (Data Guard); TAF may also be customized through its callback interface.

Hope this helps, Kuassi

joeNOSPAM_at_BEA.com wrote:
> Hi Kuassi, could you discuss the ramifications of these
> TAF considerations as it relates to JDBC?
>
> (metalink registration required)
> http://metalink.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=97926.1
>
> Under what conditions would a running JDBC application
> suffer from "Continuing work on existing cursors may raise an error
> (eg: ORA-25401 "cannot continue fetches")"? Will existing
> PreparedStatements
> ever become defunct?
>
> When will JDBC queries fail with "Failed over selects may raise an
> error"
> and what error?
>
> Do JDBC connections ever rely on having altered the session state with
> such calls as "ALTER SESSION SET NLS_DATE_FORMAT='YYYY-MM-DD';"
> or global temp tables, which will be lost on failover?
>
> If a JDBC client is using the Oracle OCI driver, doing transactions,
> how/when
> to they know that a failover occurred so they know to roll back?
>
> thanks,
> Joe
Received on Fri Sep 15 2006 - 00:18:10 CDT