Re: BCHR Tuning

Jared,

Thanks for the note - I loved the closing lines especially.

I have to say that I've already spotted two error in my note, one of them a silly slip, but the other is likely to cause confusion.

Silly slip - in the bit about decreasing block sizes -

    Good point - especially in Oracle 9; and especially if the     waits are for UNDO blocks, although that might (depending on     the nature of the activity) increase the waits on segment header     blocks

• That should have been "on the UNDO segment header blocks" in the last phrase - referring to the fact that a large transaction has to update its undo segment header block every time it fills an undo block and crosses into a new undo block.

Confusing comment - in the bit about the 'gap'

    WHEN does increasing the pctused to pctfree gap help ? And     should this be done by increasing the PCTFREE or decreasing     the PCTUSED -

• It's a mistake I make quite often because of the image of two lines across a data block representing the pctused and pctfree levels. To push the pctfree line UP, you have to DECREASE the pctfree value - and the entire paragraph was written from the perspective of moving the lines, not changing the numbers.

Regards

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

Coming soon a new one-day tutorial:
Cost Based Optimisation
(see http://www.jlcomp.demon.co.uk/tutorial.html )

Next Seminar dates:
(see http://www.jlcomp.demon.co.uk/seminar.html )

____England______January 21/23
____USA_(CA, TX)_August

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

-----Original Message-----
>
>Thanks Jonathan, for a breakdown on the cause and cure
>of buffer busy waits.
>

 . . .

>
>The abstract for one of Niemic's presentation at IOUG states
>that folks trying to encourage others to use some intelligence in
>maintaining their systems must have some vested interest.
>
>This works both ways I guess. :)
>

-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Jonathan Lewis
  INET: jonathan_at_jlcomp.demon.co.uk

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).