HPE Shadowbase Database Recovery Software

Return a Corrupted Database to a Known, Correct State

Database corruption in a data processing system can occur because of programming, user, or administrative staff errors, or other types of errors.

Miles Holenstein

HPE Shadowbase UNDO & REDO

Restore a Corrupted Database to a Correct State

Database corruption could prevent an application program that depends upon the database from behaving properly or cause the application to return erroneous results, either of which could have serious financial or other consequences.

Related Content
Publications: HPE Shadowbase Data Recovery Software: UNDO & REDO

HPE Shadowbase UNDO

The Shadowbase UNDO product utilizes a standard data replication engine in a modified configuration to remove the corruption while the application optionally continues its operation.

Key Features

Uses the Database Management System (DBMS) change-data to reverse the database to a state that is known to be correct
Can be performed while the application remains online and available for processing both update and read-only requests
Reads the DBMS change-queue to access the events involved in the corruption when database corruption is known or suspected
Reads from either the start point of corruption to the end point, or conversely, from the end point to the start point, frequently supplied as date/time values or as change-queue location values
Database changes often saved by the DBMS into an intermediate undo queue to identify the events needing undone
Can be repeated until the user is satisfied that the undo queue properly captures the corruption events
Events in the undo queue are read, processed, and applied in reverse order to the original occurrence in order to back out or undo the original changes:
  • A commit work is replaced by a begin work
  • A begin work is replaced by a commit work
  • An insert is replaced with a delete
  • A delete is replaced by an insert
  • The before and after images of an update are switched (the after image of the update is applied)

HPE Shadowbase REDO

The architecture for Shadowbase UNDO is leveraged to provide another database restoration product, Shadowbase REDO, which “rolls forward” selected database changes onto an earlier (typically saved) copy of the database.

Key Features

Creates an up-to-date database that excludes certain operations that are deemed inappropriate or undesirable
Generates helpful reports from the undo or redo queues to aid in determining the period of corruption and the contributing sources
The corrective activity scope is specified by a user or system administrator and includes a time or transaction range, a list of affected files and tables, and a list of sources of corrupted transactions