??: [SPAM] dynamic views cosnstency, do they use UNDO?

  • From: "Serol_Luo \(BJ\)" <Serol_Luo@xxxxxxxxx>
  • To: <ax.mount@xxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
  • Date: Tue, 5 Sep 2006 08:19:02 +0800

Some test can be built like below.
 
Begin
For I in 
(select * from v$session ) loop
 dbms_lock.sleep(...);
--- Fetch data, do something 
end loop;
 
 
==============================
Regards.
Serol Luo, From Peking,China
Or call me RollingPig
http://rollingpig.itpub.net
 
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???: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]?? 
amonte
????: 2006?9?5? 6:14
???: oracle-l@xxxxxxxxxxxxx
??: [SPAM] dynamic views cosnstency, do they use UNDO?
???: ?
 
Hi
 
Since v$ views based on x$ are memry structures I guess there is no guarantee 
that they would give a consistent view correct? For example in some busy 
systems, for example a 2500 users CRM system running joins of v$ views is time 
consuming, for example if I try to join v$sesstat with v$session it takes 
really a while. 
 
If let's say it takes 10 seconds does Oracle guarantee the values I am seeing 
are from 10 seconds ago? I am pretty sure undo is not used for memory 
structures or wrong?
 
I Cant seem to find a easy way to test this.
 
TIA
 
Alex
 
 
 

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