When using standby databases sometimes the unexpected happens, where you are faced with a standby that still requires recovery (archive logs need to be applied), but the archive logs are no longer available, creating an "unrecoverable archive log gap". There are a number of reasons this may happen, human error, corruption, or disk failures to name just a few. In short, the standby database needs more recovery and without the required logs, recovery from this scenario might seem impossible. Another issue seen on a regular basis is when “nologging” operations are being performed on the primary database. The end result is that these operations are not applied to the standby due to no redo information being available for these transactions. The standby will appear to be up to date, but when these objects are accessed – when standby is open read-only, roles were changed with the primary or it is activated – you will receive errors.
Prior to Dbvisit Standby release 6.0.34, the only options available to recover from these types of issues were to either recreate the standby database using the “Create Standby Database” (CSD) feature, or by manually performing incremental backups on the primary, and using that to recover the standby database. See here for more details on how this can be done. With release 6.0.34, a new option called “Synchronize Standby Database” was added to assist you with quick and easy re-synchronizing of the standby database with the primary. The process is now fully automated with minimal input required from the end user.
Watch this explanatory video for an overview of the Sync Feature:
The following two sections will show how you can perform this task from the GUI and the command line.