RE: Okay to set undo to auto extend
From: Powell, Mark <mark.powell2_at_hp.com>
Date: Tue, 6 Apr 2010 19:14:09 +0000
Message-ID: <7C4BF3B32B80CC44AE37D31B172415934CE0CCFE51_at_GVW1337EXC.americas.hpqcorp.net>
I am against using auto-allocate for undo tablespaces. You should determine how much undo you need and how much you can afford to allocate, then allocate it. I do not see a point in allocating undo with extendable data files then wating it extend to max bytes. Just allocate the space to begin with.
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of David Fitzjarrell Sent: Monday, April 05, 2010 11:29 AM
To: po04541_at_yahoo.com; Oracle L
Subject: Re: Okay to set undo to auto extend
From: patrick obrien <po04541_at_yahoo.com> To: Oracle L <oracle-l_at_freelists.org> Sent: Mon, April 5, 2010 11:08:23 AM
Subject: Okay to set undo to auto extend
Date: Tue, 6 Apr 2010 19:14:09 +0000
Message-ID: <7C4BF3B32B80CC44AE37D31B172415934CE0CCFE51_at_GVW1337EXC.americas.hpqcorp.net>
I am against using auto-allocate for undo tablespaces. You should determine how much undo you need and how much you can afford to allocate, then allocate it. I do not see a point in allocating undo with extendable data files then wating it extend to max bytes. Just allocate the space to begin with.
When the undo tablespace is fixed Oracle ignores undo_retention and uses the entire tablespace as best it can before overwriting. See the documentation.
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of David Fitzjarrell Sent: Monday, April 05, 2010 11:29 AM
To: po04541_at_yahoo.com; Oracle L
Subject: Re: Okay to set undo to auto extend
I'm curious as to why you'd set autoextend on and not set a maxsize? You'll still need to monitor how much disk space is being allocated but you'll have a stopping point to keep the UNDO from taking all of the available space if the odd transaction hits that consumes unusually large amounts of UNDO.
David Fitzjarrell
From: patrick obrien <po04541_at_yahoo.com> To: Oracle L <oracle-l_at_freelists.org> Sent: Mon, April 5, 2010 11:08:23 AM
Subject: Okay to set undo to auto extend
Oracle Admins,
My Oracle 10.2 Undo tablespace Auto Extend feature is not turned on.
That seems old school me.
Any body know of a good reason, other than to watch available disk space, to no utilize auto extend for my undo table space?
Thank you,
POB.
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