To set the minimum undo retention period:
UNDO_RETENTIONin the initialization parameter file.
UNDO_RETENTION = 1800
- Using the
ALTER SYSTEMstatement to change
ALTER SYSTEM SET UNDO_RETENTION = 1800;
Be careful, once you change UNDO_RETENTION parameter, the effect will be immediately and it effected undo tablespace, so make sure your disk have enough space disk. If disk doesn’t enough, your client / application connection to database server will be unstable.