"Richard Foote" <richard.foote_at_bigpond.com> wrote in message
news:JkPmb.166170$bo1.139819_at_news-server.bigpond.net.au...
> "Jonathan Lewis" <jonathan_at_jlcomp.demon.co.uk> wrote in message
> news:bne9sm$kog$2$8302bc10_at_news.demon.co.uk...
> >
> > Note in-line
> >
> > --
> > Regards
> >
> > Jonathan Lewis
> > http://www.jlcomp.demon.co.uk
> >
> > The educated person is not the person
> > who can answer the questions, but the
> > person who can question the answers -- T. Schick Jr
> >
> >
> > One-day tutorials:
> > http://www.jlcomp.demon.co.uk/tutorial.html
> > ____Belgium__November (EOUG event - "Troubleshooting")
> > ____UK_______December (UKOUG conference - "CBO")
> >
> >
> > Three-day seminar:
> > see http://www.jlcomp.demon.co.uk/seminar.html
> > ____UK___November
> >
> >
> > The Co-operative Oracle Users' FAQ
> > http://www.jlcomp.demon.co.uk/faq/ind_faq.html
> >
> >
> > "Anurag Varma" <avdbi_at_hotmail.com> wrote in message
> > news:E7plb.14636$4s3.2498_at_news01.roc.ny...
> > >
> > >
> > > If a table is frequently scanned (i.e. very hot), it is going to
> > remain in the
> > > buffer pool no matter what. Its no good use putting it in the KEEP
> > pool.
> > >
> >
> > A little known detail about tablescans in 8.1 (and probably 9.2 but I
> > don't recall confirming it) is that the touch count on blocks subject
> > to tablescans is NOT increased - so even if a "small" table is loaded
> > into the middle of the LRU chain and repeatedly scanned, it will
> > always end up falling off the end of the LRU chain as other blocks
> > are read into the buffer. It never gets promoted to the hot end unless
> > it is also subject to indexed accesses.
> >
>
> Hi Jonathan,
>
> That's a good point. Only the segment header which is read via a single
> block read is subject to a touch count increment during a tablescan.
>
> And yes, it's still correct in 9.2.
>
> Cheers
>
> Richard
>
>
Jonathan,
Yes I agree .. that for full table scans, the touch counts
are not increased. It increases only under indexed access.
A simple test on 9i shows that its true.
Anurag
Received on Sun Oct 26 2003 - 15:14:17 CST
