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Home -> Community -> Mailing Lists -> Oracle-L -> Re: Re: cardinality in query plans?
As I said pr eviously we had a problem, we fixed using NO_MERGE hint,
The reason was the new view complexity in 9i
now if you can't still solve your problem, I suggest you to set that
parameter, and try.
searching hidden parameters I found the name
select
ksppinm,
ksppstvl
from
x$ksppi a,
x$ksppsv b
where
a.indx=b.indx and
substr(ksppinm,1,1) = '_';
try setting _complex_view_merging=FALSE
Any way some body please knows where to do a search in this list?
> we are not using views.
> >
> > From: "Juan Cachito Reyes Pacheco" <jreyes_at_dazasoftware.com>
> > Date: 2004/03/16 Tue AM 10:24:20 EST
> > To: <oracle-l_at_freelists.org>
> > Subject: Re: cardinality in query plans?
> >
> > Hi, you are using views
> > there is a hidden parameter to disable new cbo feature for view
complexity,
> > I think this will solve your problem, but I don't remember the name.
> > ----- Original Message -----
> > From: <ryan.gaffuri_at_cox.net>
> > To: <oracle-l_at_freelists.org>
> > Sent: Monday, March 15, 2004 9:50 AM
> > Subject: cardinality in query plans?
> >
> >
> > > I'm doing a two table join and both tables are analyzed. Oracle is
> > incorrectly choosing a full tables scan over an index search(I tested
it,
> > index search has 1/4 the logical I/Os).
> > >
> > > When I see the cardinality for the full tablescan I see 262,000.
However,
> > when I do a count(*) of the table or check num_rows in dba_tables I see
> > 870,000 records. I'm assuming this is why Oracle is choosing the full
table
> > scan.
> > >
> > > table is analyzed as follows:
> > >
> > > exec dbms_stats.gather_table_stats(cascade=>true).
> > >
> > > this interesting part is that when I use bind variables Oracle chooses
the
> > proper plan. Any ideas?
> > >
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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 Mar 16 2004 - 09:51:01 CST
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