After running the 'Purge Obsolete Workflow Runtime Data' do you still have high counts in your workflow tables? Try the new PO Purge Workflow Script which was designed to identify and abort Purchasing workflows not being processed by the purge obsolete process that meet these conditions:
- Workflows attached to purchase orders or requisitions that are already approved
- Workflows not attached to purchase orders or requisitions tables
- Account generator workflows and children processes associated .
Make running this script part of your Procurement Workflow best practices. See Doc ID 458886.1 to download the script and for all the information you need.