Parameter _rollback_segment_count can cause trouble

Just some weeks ago we've learned that setting the hidden underscore parameter:

_rollback_segment_count

may cause trouble during upgrade. This parameter is used in very rare cases to have under all circumstances and situations this specified number of UNDO's online. Now during upgrade this may result in massive latch contention due to bug14226559 - and there's a patch available as well. Recommendation is to unset it during upgrade.

I don't think that many people will hit this as I personally haven't seen databases with this underscore in their init.ora or spfiles. So take this post more or less as a reminder for myself :-)

Comments:

Post a Comment:
Comments are closed for this entry.
About

Mike Dietrich - Oracle Mike Dietrich
Master Product Manager - Database Upgrade & Migrations - Oracle Corp

Based near Munich/Germany and spending plenty of time in airplanes to run either upgrade workshops or work onsite or remotely with reference customers. Acting as interlink between customers/partners and the Upgrade Development.

Follow me on TWITTER

Contact me via LinkedIn or XING

Search

Archives
« April 2015
SunMonTueWedThuFriSat
   
2
3
4
5
6
7
8
9
11
12
13
15
17
18
19
22
24
25
26
27
28
29
30
  
       
Today
Oracle related Tech Blogs
Slides Download Center
Visitors since 17-OCT-2011
White Paper and Docs
Workshops
Viewlets and Videos
This week on my Rega/iPod/CD
Workshop Map
Upgrade Reference Papers