Comments on: Collaborate 2007 – Day 1 http://www.pythian.com/news/430/collaborate-2007-day-1/ News and views from Pythian DBAs Fri, 10 Feb 2012 13:01:25 +0000 hourly 1 http://wordpress.org/?v=3.0.4 By: Alexander Fatkulin http://www.pythian.com/news/430/collaborate-2007-day-1/#comment-37814 Alexander Fatkulin Mon, 16 Apr 2007 23:11:27 +0000 http://www.pythian.com/blogs/430/collaborate-2007-day-1#comment-37814 "Kirti described a bit in Oracle 10g release 2 (associated with the automatic undo retention tuning), where the database uses more UNDO in release 2 than release 1 if you are using fixed size files." That is because undo_retention is ignored in 10GR2 for non-autoextend (unless you are in guarantee mode) mode. 10GR2 automatically tunes for maximum retention unless you are using autoextend=on. Oracle just keep as much undo as it can regardless of the undo_retention. This is documented in 10GR2 manuals. “Kirti described a bit in Oracle 10g release 2 (associated with the automatic undo retention tuning), where the database uses more UNDO in release 2 than release 1 if you are using fixed size files.”

That is because undo_retention is ignored in 10GR2 for non-autoextend (unless you are in guarantee mode) mode. 10GR2 automatically tunes for maximum retention unless you are using autoextend=on.

Oracle just keep as much undo as it can regardless of the undo_retention. This is documented in 10GR2 manuals.

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