Re: Index management

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Mon, 3 May 2004 07:36:09 +0000 (UTC)
Message-ID: <c74sp9$fhc$1@hercules.btinternet.com>

I think index prefetching may be an Oracle 9 thing, but there are so many versions out now that my memory of when something appearedd (as opposed to when it was published, announced or working) sometimes fails me.

Look in the 10053 traces for lines line:

Index prefetching is on for index XXX

especially on index full scan paths.

(just because it's on, by the way, doesn't mean you'll see it happen in a 10046 wait trace).

-- 
Regards

Jonathan Lewis
http://www.jlcomp.demon.co.uk

The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html

June  2004      UK - Optimising Oracle Seminar
July 2004 USA West Coast, Optimising Oracle Seminar
August 2004 Charlotte NC, Optimising Oracle Seminar
September 2004 USA East Coast, Optimising Oracle Seminar
September2004 UK - Optimising Oracle Seminar

"Noons" <wizofoz2k_at_yahoo.com.au> wrote in message
news:4094e4c7$0$12033$afc38c87_at_news.optusnet.com.au...


> Interesting.  In which version have you found this?

> A long time ago Oracle had an asynch process that

> performed read aheads for table scans.  In V4, IIRC.

> It went away with V6 and DMBR replaced it.  I think at

> some stage there was talk of it being re-introduced, around

> the 9i release, for any long scan.  Not sure if it ever was

> or if it fell away.  This might be a left-over from that

> idea.  Makes sense too.

>

> -- 

> Cheers

> Nuno Souto

Received on Mon May 03 2004 - 02:36:09 CDT