Question & Answer
How to roll back the last GCD Modification?
Some changes to the FileNet Content Engine Domain can prevent the Administrator/user from logging back into FEM to undo the changes. This procedure is useful in those circumstances.
Note: Take a back up of the GCD database before performing any operations on the Database.
Every update to the GCD will be stored as a new row in the FNGCD table in the GCD database referenced by the data sources listed in the CEMPBootstrap properties. The FNGCD table holds the history of the last 100 changes made to the GCD, which makes it easy for an administrator to rollback the GCD updates.
The FNGCD table consists of four columns: epoch_id, gcd_blob, last_modified_date and last_epoch_id.
The last_epoch_id of the 0 th epoch_id row decides the latest gcd_blob to be loaded. In the following screen shot The 0th epoch_id has a last_epoch_id of 15. So during CE server start up the gcd_blob where epoch_id = 15 will be loaded as the current GCD.
To undo the last modification, the user has to change the last_epoch_id of the 0th row epoch_id to 14 and make sure to change the epoch_id 15 to some negative number (-15 in the below screen shot) as shown below.
The epoch_id 15 is changed to -15, a best practice is to simply multiply the target row's epoch_id by -1 (e.g., -15) so that it can be easily determined where this 'rolled back' row was originally located. All negative-valued epoch_ids are ignored. Please note, however, that the next GCD update will produce a row with an epoch_id matching the one previously rolled back (in this case the new row will have an epoch_id of 15).
Steps to undo the last GCD update
1) Stop the Content Engine server
2) Back up the the GCD database
3) Update the FNGCD table as mentioned above
4) Re-start the Content Engine server
5) Verify the GCD configuration through FEM
6) Repeat steps 1 through 5 until user gets the desired GCD configuration
17 June 2018