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. :)
>
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