This site collects information about the Where Used Framework, also about the practical usage.
The WUF can be performed in a foreground also in a background view.
For background processing kindly consider SAP Note 2176396 - WUF displaying incorrect results after background run
There is however a difference between the display method of the dependencies in background and foreground due to the different processing of the backround job. The background job defines dependencies for the selected entries in 50 entries/package batches. Therefore the results are displayed in 50 entries packages. You can use the "switch packages" buttons to navigate between packages. The foreground mode however displays all results in one view window.
WUF ''trash button'' (Delete Objects):
With this transaction you can customize which object types to be taken into consideration when the WUF is searching for dependencies for an entry.
Database table to check quicker whether the dependency is active: WUF_OBJ and WUF_SOBJ.
If you would like to see what happens in the coding during dependency checks for different objects, then for debugging the Where-used list process (eg. during execution of transaction WUF) you can set breakpoints to the class's methods, for the respective object as listed in WUF_OBJCUST transaction. Search classes with: /SAPAPO/CL_PROD_SOBJ*
E.g. during Product-Location checks you would like to see how Live cache orders are scanned:
Class Name: /SAPAPO/CL_PROD_SOBJ_LCORDER > method IF_WUF_SOBJECT~QUICK_READ_SOBJECTS > this is checking if there are any dependencies in the first place
Class Name: /SAPAPO/CL_PROD_SOBJ_LCORDER > method IF_WUF_SOBJECT~GET_SOBJECTS > this is checking , what are those dependencies, if you click on the exact object on the screen (these will be listed under the object)
WUF is a framework, that determines the whole dependency network for objects you have selected. The dependency checklist can be extensive in general. You can see what dependencies are checked in WUF_OBJCUST transaction for each object. When measuring performance, it is always recommended to run a ST12 or SAT ABAP trace, that can reveal the weakest spots during the run-time. It is possible that there are performance-related correction SAP Notes are existing to fix the bottleneck.
2116179 - About Product Master Data Deletion or Archiving Master Data Tables in SCM APO
1945654 - Performance problem during deletion of locations - for /sapapo/delete_locations
1989700 - How to delete transactional data in APO
2561358 - WUF: ATP orders cannot be deleted
2002591 - Deletion of product in APO
2002459 - Deletion of Location Product in APO
2002536 - Deleting Location Product for Location Warehouse in table /SAPAPO/MATLWH