Automatic Tuning of Undo Retention Common Issues
(Doc ID 1579779.1)
Last updated on DECEMBER 30, 2019
Oracle Database - Enterprise Edition - Version 18.104.22.168 to 22.214.171.124 [Release 12.1] Oracle Database - Enterprise Edition - Version 10.2.0.1 to 126.96.36.199 [Release 10.2 to 11.2] Oracle Database Cloud Schema Service - Version N/A and later Oracle Database Exadata Express Cloud Service - Version N/A and later Oracle Database Exadata Cloud Machine - Version N/A and later Information in this document applies to any platform.
This document is intended to address the most popular and common issues with the Automatic Tuning of Undo Retention. Oracle Database automatically tunes the undo retention period based on how the undo tablespace is configured. o If the undo tablespace is configured with the AUTOEXTEND option, the database dynamically tunes the undo retention period to be somewhat longer than the longest-running active query on the system. o If the undo tablespace is fixed size, the database dynamically tunes the undo retention period for the best possible retention for that tablespace size and the current system load. This best possible retention time is typically significantly greater than the duration of the longest-running active query.
For more infomration, please visit the Oracle Documentation Guide found via the following link: http://docs.oracle.com/cd/B28359_01/server.111/b28310/undo002.htm
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