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Home -> Community -> Usenet -> c.d.o.server -> Re: I've now, officially, seen it all...
Andreas Sheriff wrote:
> "Charles Hooper" <hooperc2000_at_yahoo.com> wrote in message
> news:1168562149.380273.162890_at_51g2000cwl.googlegroups.com...
> > Andreas Sheriff wrote:
> >> Of course, the subject of this post is completely fictitious, so don't
> >> flame
> >> me. :-D
> >>
> >> Does anyone have any idea why someone in their right mind would need a
> >> SQL
> >> statement such as the following:
> >>
> >> SELECT NULL FROM DUAL FOR UPDATE NOWAIT
> >>
> >> Does this make sense? Did I actually loose it?
> >>
> >> Andreas
> >
> > A little test:
> >
> > Session 1:
> > SQL> SELECT NULL FROM DUAL FOR UPDATE NOWAIT;
> > N
> > -
> >
> > Session 2:
> > SQL> SELECT
> > 2 *
> > 3 FROM
> > 4 V$LOCKED_OBJECT;
> >
> > XIDUSN XIDSLOT XIDSQN OBJECT_ID SESSION_ID ORACLE_USERNAME
> > OS_USER_NAME PROCESS LOCKED_MODE
> > 6 18 14870 258 193 SYS hooper
> > 804:212 3
> >
> > SQL> UPDATE DUAL SET DUMMY='A';
> >
> > Session 2 hangs waiting for session 1 to commit or rollback.
> >
> > Session 1:
> > SQL> ROLLBACK;
> > Rollback complete.
> >
> > Session 2:
> > 1 row updated.
> >
> > SQL> ROLLBACK;
> > Rollback complete.
> >
> > This is obviously an attempt to allow only one session at a time to
> > update the DUAL table. :-)
> >
> > Charles Hooper
> > PC Support Specialist
> > K&M Machine-Fabricating, Inc.
> >
>
>
when are they finally going to support that often requested role of "UPDATE ANY DICTIONARY"? Received on Fri Jan 12 2007 - 01:24:56 CST
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