How to Keep All UNDO Segments from Being Offlined in Oracle 10g - Fast Ramp-Up
Last updated on FEBRUARY 27, 2017
Applies to:Oracle Database - Enterprise Edition - Version 10.2.0.1 to 10.2.0.5.0 [Release 10.2]
Information in this document applies to any platform.
***Checked for relevance on 10-Oct-2016***
The purpose of this document is to explain how Oracle 10g uses Automatic Workload Repository (AWR) statistics to decide how many undo segments should be online when an instance is started.
Per the Oracle Database 10g New Features for Administrators Course, the concept of Fast Ramp-Up indicates the following:
"In previous versions, when the instance was restarted or when you switched undo tablespaces, the ramp-up time for the system to grow the number of online undo segments could be several minutes. Generally, this time delay was unacceptable.
After an instance startup or a switch of undo tablespaces in Oracle Database 10g, the database decides how many segments to place online, based on existing data stored in the the AWR."
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