The trail recovery process has the ability to, in some cases, automatically rebuild trail files that are corrupt or missing by Oracle GoldenGate. When an Extract pump restarts, if the last trail that the pump was writing to is missing, then the Extract pump attempts to rebuild the missing trail file on the target system. This is done automatically using the checkpoint information for the process and the last valid trail file. The Replicat process automatically skips over any duplicate data in the trail files that have been rebuilt by the new trail recovery feature. This recovery will occur as long as there is at least 1 target trail from this sequence and that the trail files still exist on the source where the Extract pump is reading them.

This process can also be used to rebuild corrupt or invalid trail files on the target. Simply delete the corrupt trail file, and any trail files after that, and then restart the Extract pump. With this new behavior, Oracle recommends that PURGEOLDEXTRACTS MINKEEP rules are properly configured to ensure that there are trail files from the source that can be used to rebuild the target environment. This feature requires that Oracle GoldenGate release 12.1.2.1.8 or greater is used on both the source and target servers. Do not attempt to start the Replicat with NOFILTERDUPTRANSACTIONS because it will override Replicat's default behavior and may cause transactions that have already been applied to the target database to be applied again.