UNDO tablespace increasing and not release space

UNDO tablespace increasing/growing and not release space

Applies to: 

Oracle Database 10gR2

Description:

Undo tablespace start growing abnormally. UNDO_RETENTION parameter is set to 900 seconds, but undo data did not release the space. After doing some research work, I found the following solution:

Solution:

Set the following hidden parameter in init.ora file and check the free space in undo tablespace after 3-4 Hrs.

_smu_debug_mode=33554432

or

SQL> Alter system set "_smu_debug_mode" = 33554432;

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About the Author

Rana Abdul Wahid is an Oracle Database Administrator (DBA) with expertise in Oracle RMAN recovery, Oracle EBS administration, backup and recovery, performance tuning, database cloning, and troubleshooting critical Oracle database issues.