Question & Answer
Question
Cause
Answer
Every update to the GCD is stored as a new row in the FNGCD table in the GCD database. The FNGCD table holds the history of the last 100 changes made to the GCD. Using the procedure documented in this technote makes it easy for an administrator to roll back the unwanted 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 0th epoch_id row identifies the last gcd_blob that was loaded. In Figure 1, the 0th epoch_id has a last_epoch_id of 15. When the Content Platform Engine server starts, the gcd_blob where epoch_id = 15 is loaded as the current GCD.
To undo the last modification in the FNGCD table shown in Figure 1
- Change the value of the last_epoch_id in the 0th row to 14.
- Change the value of epoch_id 15 to a negative number. For instance, change the value to -15.
Best Practice
Multiply the epoch_id of the change that is to be rolled back by -1. All negative-valued epoch_ids are ignored, and this enables you to track changes that have been undone. Note that the next GCD update produces a row with an epoch_id matching the one previously rolled back. In the example shown in this technote, the new row is assigned an epoch_id of 15.
Figure 2: FNGCD table with a value of 14 for the last_epoch_id in the row with 0 (zero) as the epoch_id
Steps to undo the last GCD update
- Stop the Content Platform Engine server.
- Back up the GCD.
- Update the FNGCD table as described to change the epoch_id of the last row in the table to a negative number. And, update the last_epoch_id of the 0th row to match the epoch_id of the row with the last good update.
- Restart the Content Platform Engine server.
- Verify the logon to ACCE is successful.
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Document Information
Modified date:
22 February 2023
UID
swg21318059