RE: Are any of you guys managing rollback segments manually?
Date: Tue, 23 Aug 2016 14:43:02 +0000
Message-ID: <CE70217733273F49A8A162EE074F64D901503393F1_at_exmbx05.thus.corp>
I recall seeing a case in the early days of automatic undo where a very big serial DML batch had a problem because due to the cost of stealing a very large number of unexpired undo extents while it ran; and then everything running at 9:00 having a problem because all the small(ish) concurrent DML stuff from the end users had to steal the extents back - and that caused a massive contention problem for a few minutes.
If someone had run into that problem they might have decided to run with manual rollback and specify a particular segment in a separate tablespace for the batch job as a workaround.
Regards
Jonathan Lewis
http://jonathanlewis.wordpress.com
_at_jloracle
From: oracle-l-bounce_at_freelists.org [oracle-l-bounce_at_freelists.org] on behalf of Chris Taylor [christopherdtaylor1994_at_gmail.com] Sent: 23 August 2016 15:03
To: ORACLE-L
Subject: Are any of you guys managing rollback segments manually?
I was having a discussion with a guy about improving data load speeds and he was asking me about creating a large rollback segment and how I would handle it. I was a bit taken aback because I haven't manually managed rollback segments in a long, long time.
So, I'm curious if this is still "a thing"? Managing rollback segments manually especially in regard to large data loads?
If so, I'd like to understand why managing rollback segments manually makes more sense than using a dedicated UNDO tablespace and letting Oracle manage the rollback segments?
I've been googling some this morning and I see some bits and pieces here and there but I don't see any use cases where managing rollback segments manually makes sense to me. (So I'm trying to put 2+2 together in my own mind)
Regards,
Chris
-- http://www.freelists.org/webpage/oracle-lReceived on Tue Aug 23 2016 - 16:43:02 CEST