Re: TAF with Oracle RAC

  • From: Chris Taylor <christopherdtaylor1994@xxxxxxxxx>
  • To: softice@xxxxxxxxx
  • Date: Thu, 23 Jul 2015 10:51:22 -0500

I thought Chris' problem was that the *application *was getting an error
but the session itself fails over correctly.

If I understand the problem, doesn't this relate to whether the application
supports TAF internally or not? I thought the application had to be coded
to be able to take advantage of TAF because as far as I know Oracle will
always return a message to the application if the session gets failed over.

Regards,
Chris Taylor

On Thu, Jul 23, 2015 at 9:22 AM, Svetoslav Gyurov <softice@xxxxxxxxx> wrote:

Hi Chris,

Does the service mydb.domain is configured as TAF ? Also with the
preconnect method shouldn't you specify the backup connection as well as
part of the connection string ? Why not try the basic method first ?

Add TAF service:
srvctl add service -d orcl -s mydb -l PRIMARY -m BASIC -e SELECT -w 1 -z
180 -q TRUE

Connection string:
mydb =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = my.scan.listener )(PORT = 1521)
)
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME=mydb.domain)
(FAILOVER_MODE =
(TYPE = SELECT)
(METHOD = BASIC)
)
)
)

The failover parameters should be inherited from the service anyway.

Then simply check whether the established sessions are supporting TAF:
SELECT MACHINE, FAILOVER_TYPE, FAILOVER_METHOD, FAILED_OVER, COUNT(*)
FROM V$SESSION
GROUP BY MACHINE, FAILOVER_TYPE, FAILOVER_METHOD, FAILED_OVER;


Regards,
Sve

On Thu, Jul 23, 2015 at 1:43 PM, Chris King <ckaj111@xxxxxxxx> wrote:

The client software is a full oracle client installation.

Is my understanding correct, that the scan listener should enable session
continuation without errors if one node goes down? With my current set up,
connectivity is re-established but the user gets an oracle error first.
Does this mean something is not properly configured? And if so, what should
I be looking at?
Thanks all!

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