Re: UNDO: 10g-style behaviour in 220.127.116.11?
Date: Sat, 11 Apr 2009 14:52:46 +0100
"Hemant K Chitale" <hemantkchitale_at_gmail.com> wrote in message
> Yes, there is one significant difference (other than Retention
> It is called "Automatic Undo Retention" . Automatic Undo Management
> behaviour differs depending on whether the datafiles in the Undo
> tablespace are set to AutoExtend ON or AutoExtend OFF.
> In the AutoExtend ON case, the value you set for "undo_retention" is
> the floor value but Oracle automatically ajdusts the actual
> undo_retention it uses on the basis of query durations -- this you
> will see in MAXQUERYLEN and and TUNED_UNDORETENTION in V$UNDOSTAT.
I can't recall seeing anything that says the value you set is the floor
a reference would be useful as I've had one client run into problems with automatic undo retention in 10.2.0.3 where the tuned_undoretention dropped to a value much lower than their setting. There particular circumstances made
this a bit of a threat.
-- Regards Jonathan Lewis http://jonathanlewis.wordpress.com Author: Cost Based Oracle: Fundamentals http://www.jlcomp.demon.co.uk/cbo_book/ind_book.html The Co-operative Oracle Users' FAQ http://www.jlcomp.demon.co.uk/faq/ind_faq.htmlReceived on Sat Apr 11 2009 - 08:52:46 CDT