Lex and all, I am more inclined with this possible confusion with instructor as you describe below. BTW, this instructor is from big O. Thanks for all the replies ... looks like we will have some blockdumps today. .. Raj On Fri, 3 Sep 2004 10:59:40 +0200, Lex de Haan <lex.de.haan@xxxxxxxxxxxxxx> wrote: > I think the instructor (in case he/she wasn't joking in the first place) > mixed things up a little here. > I am guessing, but I assume he/she was referring to the fact that the CBO > may use segment header info to estimate the costs of a full table scan in > the absence of table statistics. > > well, there is some distinct relationship between the two queries "select > count(*) from T" and "how expensive you think a FTS of table T will be" ... > > Kind regards, > Lex. --- To unsubscribe - mailto:oracle-l-request@xxxxxxxxxxxxx&subject=unsubscribe To read recent messages - //freelists.org/archives/oracle-l/09-2004