Parameters for automatic data recovery management and information for restoring data

1. Parameters for automatic management of Oracle restored data:

1. Some programs before Oracle 9i contain statements that manually specify rollback segments. This statement does not affect the final result, but reports an error on the console. Therefore, dynamic parameters are introduced.

Undo_suppress_errors: manually specifying or setting a restore segment in the mode of automatic data recovery management does not affect the final result, but no error is reported on the console.

Alter session set undo_suppress_errors = true;

2. undo_retention this parameter determines the time for restoring data to ensure read consistency. The time when the restored data is retained in the restored tablespace after the transaction is committed.

Alter system set undo_retention = timelong;

When the value of the undo_retention parameter is set, the disk space usage increases, especially when DML operations are too frequent, the system efficiency is reduced.

2. Obtain restored data information