Re: RAC gv$session
- From: Tim Gorman <tim@xxxxxxxxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Thu, 11 Mar 2004 09:40:42 -0700
SID and SERIAL# are not guarenteed unique across instances. INST_ID is the
last part of that implied primary key, for all GV$ views. Look at
V$FIXED_VIEW_DEFINITION
The data for each instance, including memory-based V$ views like V$SESSION,
is maintained solely within that instance. When necessary, those GV$ views
are populated using cross-instance queries via parallel execution ³slave²
(i.e. ³ora_pXXX_SID²) processes. Exceptions include the V$ views that are
based in the control file, such as V$DATABASE, V$THREAD, V$DATAFILE, etc.
whose data is visible to all instances through the shared control files. At
least, that is how it was done for 8/8i OPS ? I haven¹t verified whether 9i
RAC has found something more clever involving cache fusion and the
³block-shipping² processes or something. The GV$ views did not exist in
Oracle7 and prior ? we had to write them custom. Can anyone confirm or
correct about how 9iRAC displays GV$ info?
Still, although you can view SID and SERIAL# from across the cluster (though
GV$ views), you can only utilize them in ³DBMS_² package calls or from ALTER
SYSTEM KILL SESSION, etc. from the appropriate instance...
on 3/11/04 7:48 AM, Kommareddy, Srinivas (MED, Wissen Infotech) at
Srinivas.Kommareddy@xxxxxxxxxx wrote:
> Hi All,
>
> We have 2 nodes set for RAC.
>
> When I try to kill a session from node 1, is the sid,serial# going to be
> unique among the nodes,
> Or is there any possibility that another session on node 2 will be killed (if
> sid, seiral# are same for another session on node 2).
>
> Does my select sid,serial# checks v$session or gv$session.
>
> Can someone through some light on this.
>
> Tx and Regards,
> Srinivas
>
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