|Oracle Workflow Developer's Guide|
Part Number B10284-02
When you define an item type, you must also specify its persistence type. The persistence type controls how long a status audit trail is maintained for each instance of the item type. If you set Persistence to Permanent, the runtime status information is maintained indefinitely until you specifically purge the information by calling the procedure WF_PURGE.TotalPerm( ).
If you set an item type's Persistence to Temporary, you must also specify the number of days of persistence ('n'). The status audit trail for each instance of a Temporary item type is maintained for at least 'n' days of persistence after its completion date. After the 'n' days of persistence, you can then use any of the WF_PURGE APIs to purge the item type's runtime status information. See: WF_PURGE, Oracle Workflow API Reference.
If you set an item type's Persistence to Synchronous, Oracle Workflow expects instances of that item type to be run as forced synchronous processes with an item key of #SYNCH. Forced synchronous processes complete in a single SQL session from start to finish and never insert into or update any database tables. Since no runtime status information is maintained, you do not normally need to perform any purging for a process with the Synchronous persistence type. However, if you run the process with a unique item key in asynchronous mode for testing or debugging purposes, Oracle Workflow does maintain runtime status information for that process instance. You can purge this information by changing the item type's Persistence to Temporary and running any of the WF_PURGE APIs. Then change the item type's Persistence back to Synchronous. See: Synchronous, Asynchronous, and Forced Synchronous Processes, Oracle Workflow API Reference, WF_PURGE, Oracle Workflow API Reference, and Purging for Performance, Oracle Workflow Administrator's Guide.
Note: If you are using the version of Oracle Workflow embedded in Oracle Applications, you may also use the Purge Obsolete Workflow Runtime Data concurrent program to purge obsolete item type runtime status information. The executable name for this concurrent program is "Oracle Workflow Purge Obsolete Data" and its short name is FNDWFPR. See: Purge Obsolete Workflow Runtime Data, Oracle Workflow API Reference.