Disabling Oracle Flashback Query

Status

If you are...

This task is...

Installing a new iProcess Engine Version 11.8.0

N/A

Upgrading from an iProcess Engine Version 11.0 or later

Possibly required

Database

Oracle

Description

Oracle has a flashback query feature, which lets you view and repair historical data. (The initialization parameter, UNDO_RETENTION, provides a means of explicitly specifying the amount of undo information to retain.)

If flashback query is enabled, the amount of undo tablespace required while you are upgrading (see Creating an Oracle UNDO Tablespace for details) will increase significantly. Therefore you may want to disable this feature while you are upgrading the iProcess Engine or Process Engine.

However, this may not be possible if there are other applications that use the same database and that may require a flashback query while the upgrade is taking place. If that is the case, you must leave the feature enabled and make sure you have sufficient undo tablespace available.

Note 

 It is possible for undo to reach 100% as the flashback query undo will still be allocated. This will make it difficult to monitor the undo tablespace.

If undo is set to autoextend, it may grow extremely large as all undo transactions for the entire upgrade will be stored.

Procedure

To disable flashback query, use the Oracle command:

alter system set UNDO_RETENTION=0

See Also

See your Oracle documentation for more information about flashback query.