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Home -> Community -> Mailing Lists -> Oracle-L -> Re: Anyone seen weblogic do this?
Well, I've used x$dual in production without any problems, the only thing is
that if you are in RAC environment, you have to restrict your view to use
only your local instance's record from the table, otherwise you'll get a lot
of interconnect traffic (using where INST_ID = userenv('Instance') as the v$
views do select from gv$ ones).
But in 10g you don't have to worry about this anymore in most cases, 10g has a FAST DUAL access path, which doesn't cause any LIOs either (there is one exception I know, though).
Tanel.
> Hi Tanel,
> Do you recommend to use X$DUAL in production code (with all appropriate
> testing of course)?
> Are there hidden troubles comparing with regular DUAL table?
>
> Jurijs
> 9268222
> ============================================
> http://otn.oracle.com/ocm/jvelikanovs.html
>
>
>
>
>
>
> Tanel Põder <tanel.poder.003_at_mail.ee>
> Sent by: oracle-l-bounce_at_freelists.org
> 05.07.2004 21:17
> Please respond to oracle-l
>
> To: <oracle-l_at_freelists.org>
> cc:
> Subject: Re: Anyone seen weblogic do this?
>
>
> > >> In 8i there is no x$dual, there you could use a single table hash
> > cluster or IOT with relevant view on it to reduce dual cost (an unique
> > scan on single block IOT akes only 1 LIO compared to 3 that FTS makes on
> a
> > single block table).
> > You definitely know, but in any case FYI:
> [snip]
> > SYS:BUKA> create view mydual as select * from dual where
> > rowid='AAAADDAABAAAAHSAAA';
>
> Cool solution, I hadn't thought about the rowid solution before, I have
> used
> IOTs and single table hash clusters so far if x$dual isn't an option.
>
> Btw, I was wrong before, x$dual DOES exist in 8i as well, at least in
> 8.1.7.4.
>
> Tanel.
>
>
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-- Archives are at http://www.freelists.org/archives/oracle-l/ FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html -----------------------------------------------------------------Received on Tue Jul 06 2004 - 03:17:30 CDT
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