Processing Backflushes in Two Steps

Use

Production backflushes, which are sent from an APO system to a DI system, contain components and activities to be posted. Components can be posted either synchronously or asynchronously. Activities are always posted asynchronously. The asynchronous processing is executed during the Processing of the Backflushes (transaction PPCGO ).

If you want to backflush a high volume production process, and the number of cost collectors increases, the processing of the backflushes can lead to a deterioration in performance. This occurs, because material documents must be created for each cost collector, even if the components are the same. (This step is necessary for the postings in FI/CO.)

To avoid this deterioration in performance, you can execute the production backflush in two steps. This processing has the advantage, that the logistical data remains consistent, even if the FI/CO data is only posted once a day.

Integration

If you work with the two-step production backflush, the requirements are adjusted in APO after the first step.

Prerequisites

In order to execute the backflush in two steps, you must have maintained the values for fields Movement Type for the Two-Step Production Backflush and Storage Location for the Two-Step Backflush in your backflush profile. You maintain your backflush profile in Customizing in the DI system under Start of the navigation path Production Next navigation step Repetitive Manufacturing Production Backflush Create Backflush Profile End of the navigation path . For further information, see the F1 help for each of these fields.

All stocks are transferred from the DI system to the APO system as standard. In order to process the production backflush in two steps, it is necessary to define a dummy storage location, that is not MRP relevant.To avoid the stocks for this storage location being transferred to APO , you must implement a user exit. For further information, see note 496020.

Caution Caution

You can only process backflushes in two steps if you have fulfilled the following prerequisites:

You use materials for which you have not defined batch or stock determination rules.
The storage location is not MRP relevant.
The production backflush is not a cancellation.

When using stock determination rules, the system dynamically determines the storage location, and it is not guaranteed that the storage location is not MRP relevant.

End of the caution.

Features

To avoid a deterioration in performance in high-volume backflush scenarios, you can process the backflushes in two steps (transactions PPCGO and PPCGO2 ).

The two step production backflush works in the following way:

First Step The system reads all open backflushes and corresponding components. The quantities of components are grouped according to posting date. The system posts the components without reference to a product cost collector to a non-MRP storage location. The production backflushes are updated. The goods movements are posted. At the same time, the product cost collectors and the information about the components are stored in a new table. The backflush data is updated in APO .
Second Step
The components are grouped according to posting date and product cost collectors. The goods issues are posted per product cost collector (for example, once a day). The data in CO/FI is updated.

If errors occur in either of the steps, you can postprocess the production backflushes in transaction COGI .

The following graphic gives you an overview of both of the steps in the two-step production backflush.

This graphic is explained in the accompanying text.

The advantage of the two-step production backflush is that the logistical data is already updated before the data in CO/FI is posted. The goods movements are aggregated before they are posted, thereby improving the performance of the system.

Example

100 assemblies are produced every 30 minutes. These assemblies are made up of 500 components. After two hours, the following has been posted:

One-step Production Backflush	Transaction PPCGO is executed every 30 minutes. The system creates 100 material documents, each with 500 line items. The system therefore posts 50,000 line items every 30 minutes. In two hours, 200,000 line items are posted.
Two-step Production Backflush	Transaction PPCGO is executed every 30 minutes. The system creates 1 material document with 500 line items. After two hours, the goods issue is posted for each product cost collector from the non-MRP relevant storage locationThis, therefore, entails a posting of 50,000 line items. 52,000 line items are therefore posted.