Re: RAC Failover testing
- From: Andrey Kriushin <Andrey.Kriushin@xxxxxxxx>
- To: anuragdba@xxxxxxxxx
- Date: Sun, 27 Aug 2006 17:38:30 +0400
Hi,
Couple of comments.
1. (ENABLE=BROKEN) is used to request KeepAlive feature for TCP/IP
socket. It might be useful if Oracle's standard DCD (Dead Connection
Detection) is not working properly. I've used that option several times
up to 9i inclusive together with OS KeepAlive settings (decreasing the
check interval from usual 2 hour default). It actually helped shadow
process to terminate when the client loses connection (well known
session killing problem). I've even written an article some 6 years ago.
Anyway, this has nothing in common with the ORA-01089, as your client
had successfully recognized lost connection and then occasionally tried
to reconnect to the same server. Which is legal as long as you provided
two addresses and allow LOAD_BALANCE. Well, one may expect more
intellectual behaviour from TAF (not try the address just faulted), but
that is another question.
2. Some warning about failed over sessions, especially when TYPE=SELECT.
Don't forget, that specific session setting won't be restored after
successful failover. For example, if you'd change NLS_DATE_FORMAT from
instance default value via ALTER SESSION before your SELECT with DATE
datatype and managed to fetch some rows before the failure, than you'll
be surprised with the rest of results after failover. :-)
I would not recommend to use "out of the box" TAF if you need really
"available" application. Take this as a demo of possibilities and go for
http://download-west.oracle.com/docs/cd/B10501_01/appdev.920/a96584/oci09adv.htm#449793
There is similar chapter in JDBC documentation.
HTH
Andrey
Anurag Verma wrote:
Why this is happening, as I am using (ENABLE=BROKEN) and (TYPE=SELECT)
options???
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