Re: The same session run on both instances (RAC), is it normal?

  • From: "David Sharples" <davidsharples@xxxxxxxxx>
  • To: staywithpin@xxxxxxxxx
  • Date: Thu, 27 Sep 2007 08:08:45 +0100

its just a session id, they are not unique across instances, a session id is
not a database connection, its an instance connection and a session will
only exist on one instance

And that is not how load balancing works

On 27/09/2007, qihua wu <staywithpin@xxxxxxxxx> wrote:
> We have a two nodes RAC, the strange thing is that many sessions run on
> both nodes.
>       select sid from gv$session group by sid having count(*)>1
> they are lots of rows return.
> My understanding for load balance is:  if sessions on instance 1 are too
> many, then new session will be connected to instance 2.
> But if at the beginning there were100 sessions on both inst1 and inst2,
> after all the sessions on inst2 are completed, no existing session on
> instance1 will go to instance2.
> But the fact of the above query told me some sessions run on both
> instance. How can this be true?

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