Purging unused data and maintaining a purging methodology before an upgrade can optimize the upgrade process.
Note:
If a large amount of data needs to be purged, consider partitioning tables or employing other data optimization strategies. Using scripts to remove large amounts of data may impact performance. See the following information in Administering Oracle SOA Suite and Oracle Business Process Management Suite:Some components have automated purge scripts. If you are using purge scripts, wait until the purge is complete before starting the upgrade process. The upgrade may fail if the purge scripts are running while using the Upgrade Assistant to upgrade your schemas.
Purge the execution logs to avoid exporting and importing excessive data as part of work repository export/import. See Purging the Logs in Administering Oracle Data Integrator.
If you are migrating closed 11g instance data, run the instance purge scripts before running the upgrade. See Using Purge Scripts Before You Upgrade.