Oracle® Database Administrator's Guide 11g Release 1 (11.1) Part Number B28310-04 |
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You specify the minimum undo retention period (in seconds) by setting the UNDO_RETENTION
initialization parameter. As described in "About the Undo Retention Period", the current undo retention period may be automatically tuned to be greater than UNDO_RETENTION
, or, unless retention guarantee is enabled, less than UNDO_RETENTION
if space in the undo tablespace is low.
To set the minimum undo retention period:
Do one of the following:
Set UNDO_RETENTION
in the initialization parameter file.
UNDO_RETENTION = 1800
Change UNDO_RETENTION
at any time using the ALTER SYSTEM
statement:
ALTER SYSTEM SET UNDO_RETENTION = 2400;
The effect of an UNDO_RETENTION
parameter change is immediate, but it can only be honored if the current undo tablespace has enough space.