Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Usenet -> c.d.o.server -> Re: GROUP BY disables indexes and parallel query

Re: GROUP BY disables indexes and parallel query

From: Michael Ho <infoage_at_hk.super.net>
Date: 1997/04/14
Message-ID: <5ir54m$js7$2@tst.hk.super.net>#1/1

Dragon Fly wrote:
>
> Here is what I've got:
> SELECT A, B, C from MYTABLE WHERE A<=5 and B=9701;
> runs for 10 secs on 12-million row MYTABLE;
>
> But when I do
> SELECT A,B,COUNT(*) FROM MYTABLE WHERE A<=5 AND B=9701 GROUP BY A,B;
> runs for 20 mins.
>
> Looks like GROUP BY clause disables both indexes and parallel query on
> MYTABLE.
> Why is that and how to avoid it?

Have you explain plan for this ?

How about hint the optimizer to use index ? Received on Mon Apr 14 1997 - 00:00:00 CDT

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US