why would you not need a sort with a full index scan and need one with a
fast full scan?
----- Original Message -----
To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com>
Sent: Thursday, October 23, 2003 5:19 PM
function?
> Possibly to avoid a sort operation (assuming that you might be able to get
> away with a NOSORT when doing the full index scan)? It might be deciding
> that the benefit of the multi-block reads for the fast full scan are more
> than offset by the sort operation that would be needed (and might not be
> needed when doing the full index scan).
>
> Regards,
>
> Larry G. Elkins
> The Elkins Organization Inc.
> elkinsl_at_flash.net
> 214.954.1781
>
> > -----Original Message-----
> > From: ml-errors_at_fatcity.com [mailto:ml-errors_at_fatcity.com]On Behalf Of
> > rgaffuri_at_cox.net
> > Sent: Thursday, October 23, 2003 2:39 PM
> > To: Multiple recipients of list ORACLE-L
> > Subject: Re: index full scan over an index fast full scan in an analytic
> > function?
> >
> >
> > i cant attach the 10053 trace. it has proprietary info. There
> > isnt much in analytic explain plan either.
> >
> > does anyone know in general why a full scan would be faster than
> > a fast full scan?
> > >
> > > From: <rgaffuri_at_cox.net>
> > > Date: 2003/10/23 Thu PM 03:09:26 EDT
> > > To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
> > > Subject: index full scan over an index fast full scan in an
> > analytic function?
> > >
> > > I have an index on the two columns used in this query. Why
> > would the optimizer choose an index full scan over an index fast
> > full scan?
> > >
> > > My question isnt why an index is used, but the type of index scan?
> > >
> > > select *
> > > from (select col1, col2,
> > > dense_rank()
> > > over (partition by col1
> > > order by col2 desc)tab
> > > from mytable)
> > > where tab = 1
> > >
> > > --
> > > Please see the official ORACLE-L FAQ: http://www.orafaq.net
> > > --
> > > Author: <rgaffuri_at_cox.net
> > > INET: rgaffuri_at_cox.net
> > >
> > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com
> > > San Diego, California -- Mailing list and web hosting services
> > > ---------------------------------------------------------------------
> > > To REMOVE yourself from this mailing list, send an E-Mail message
> > > to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
> > > the message BODY, include a line containing: UNSUB ORACLE-L
> > > (or the name of mailing list you want to be removed from). You may
> > > also send the HELP command for other information (like subscribing).
> > >
> >
> > --
> > Please see the official ORACLE-L FAQ: http://www.orafaq.net
> > --
> > Author: <rgaffuri_at_cox.net
> > INET: rgaffuri_at_cox.net
> >
> > Fat City Network Services -- 858-538-5051 http://www.fatcity.com
> > San Diego, California -- Mailing list and web hosting services
> > ---------------------------------------------------------------------
> > To REMOVE yourself from this mailing list, send an E-Mail message
> > to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
> > the message BODY, include a line containing: UNSUB ORACLE-L
> > (or the name of mailing list you want to be removed from). You may
> > also send the HELP command for other information (like subscribing).
> >
>
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.net
> --
> Author: Larry Elkins
> INET: elkinsl_at_flash.net
>
> Fat City Network Services -- 858-538-5051 http://www.fatcity.com
> San Diego, California -- Mailing list and web hosting services
> ---------------------------------------------------------------------
> To REMOVE yourself from this mailing list, send an E-Mail message
> to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
> the message BODY, include a line containing: UNSUB ORACLE-L
> (or the name of mailing list you want to be removed from). You may
> also send the HELP command for other information (like subscribing).
--
Please see the official ORACLE-L FAQ: http://www.orafaq.net
--
Author: Ryan
INET: rgaffuri_at_cox.net
Fat City Network Services -- 858-538-5051 http://www.fatcity.com
San Diego, California -- Mailing list and web hosting services
---------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from). You may
also send the HELP command for other information (like subscribing).
Received on Thu Oct 23 2003 - 21:34:26 CDT
