Re: TAF with Oracle RAC

  • From: Chris King <ckaj111@xxxxxxxx>
  • To: Svetoslav Gyurov <softice@xxxxxxxxx>
  • Date: Thu, 23 Jul 2015 18:29:49 +0000 (UTC)

Thanks everyone for all your input on this issue. I think it's resolved now.
I've added the TAF service on the server side as per Svetoslav's recommendation
and changed the method to BASIC. The test results now show that the application
log received an error, but the user interface did not display any errors and it
continued processing the long query thru to completion, even though I'd brought
one node down. That's what I was looking for. 

Many thanks!
-ck

From: Svetoslav Gyurov <softice@xxxxxxxxx>
To: ckaj111@xxxxxxxx
Cc: Oracle-l Digest Users <oracle-l@xxxxxxxxxxxxx>
Sent: Thursday, July 23, 2015 10:22 AM
Subject: Re: TAF with Oracle RAC

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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