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Home -> Community -> Usenet -> c.d.o.server -> Re: Count(*) is very slow (7.3.3)
Hi,
here what I got about V733_PLANS_ENABLED from Oracle 7.3.4 docu:
V733_PLANS_ENABLED determines whether bitmap access paths will be considered for regular indexes on the tables that have at least one bitmap index.
V733_PLANS_ENABLED enables a set of specialoptimizations: GROUP BY No Sort, Index Fast Full Scans, and using B-tree indexes in
bitmap access paths provided
bitmap indexes exist on the table
Sorting can be avoided when performing a GROUP BY operation when you
know that the input data is already ordered so that all rows in each
group are clumped
together. This may be the case, for example, if the rows are being
retrieved from an index that matches the grouped columns, or if a
sort-merge join produces the
rows in the right order. ORDER BY sorts can be avoided in the same
circumstances. When no sort takes place, the EXPLAIN PLAN output
indicates GROUP
BY NOSORT.
You must set the V733_PLANS_ENABLED initialization parameter to TRUE for
GROUP BY NOSORT to be available.
satar_at_my-dejanews.com schrieb:
>
> Calm down Dave, we come here to learn. I too couldn't find fast_full_scan. But
> thank you for pointing out the v733_plans_enabled=TRUE. So this is the same
> parameter in Version 8's fast_full_scan?
>
> In article <70ogo3$2cn$1_at_nnrp1.dejanews.com>,
> smith_at_ali.com.au wrote:
> > Thanks for saying that I'm full of shit!
> >
> > In v 7.3.3 the parameter is
> >
> > v733_plans_enabled=TRUE
> >
> > See
> >
> > http://www.oramag.com/oracle/98-Jul/dba.html
> >
> > In article <70n2up$n9d$1_at_hermes.is.co.za>,
> > "Billy Verreynne" <vslabs_at_onwe.co.za> wrote:
> > > Andreas Kyritz wrote in message <70mv73$p34$1_at_news.ipf.net>...
> > >
> > > >I've got a mail with the right idea from Dave Smith from Australia.
> > > >The trick to do 'SELECT COUNT(*) FROM ATABLE' fast is, to include:
> > > > fast_full_scan_enabled=true
> > > >to the init file.
> > > >That's all and now it takes less than a second. 8-))
> > >
> > > Well methinks that someone is bullshitting someone 'cause there aint no
> > > such thing with v7.x....
> > >
> > > Is this a v8.x parameter? Comments?
> > >
> > > regards,
> > > Billy
> > >
> > >
> >
> > --
> > Dave Smith
> >
> > smith_at_ali.com.au
> >
> > -----------== Posted via Deja News, The Discussion Network ==----------
> > http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
> >
>
> --
> Oracle DBA/UNIX System Admin
> Advanced Enterprise Solutions
> (949) 756-0588
> Oracle Re-Seller
>
> -----------== Posted via Deja News, The Discussion Network ==----------
> http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
--
Regards
Matthias Gresz :-)
Matthias.Gresz_at_Privat.Post.DE
Always log on the bright side of life.
http://www.stone-dead.asn.au/movies/life-of-brian/brian-31.htm
Received on Mon Oct 26 1998 - 02:27:31 CST
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