How to Handle HVR Capture During a Database Upgrade

Question

How to handle HVR capture during a database upgrade?

Environment

HVR

Answer

A database upgrade writes a lot of data to the transaction logs. When HVR reads through the redo changes generated during the upgrade, it may run into errors. However, because a database upgrade is generally run during application downtime (rolling upgrades in a clustered environment are an exception), it is safe to skip the changes written to the transaction log during the upgrade.

While upgrading a source database, do the following to ensure there is no data loss and to avoid refreshing the data:

1. Stop the application making changes to the database.

2. Ensure log-based capture captures all changes made by the application.

3. Stop HVR capture.

4. Run the upgrade.

5. Re-initialize the capture after checking the following options:

   • Transaction Files and Capture Time
   • Transaction Files and Capture Time
   • Table Enrollment
   • Scripts and Jobs

   NOTE: If you perform this step after the application started, you can rewind the capture (assuming the transaction log backups or archived logs are still available and accessible).

6. Start (trigger in older versions) the capture.

7. Start the application.