Solution : https://service.sap.com/sap/support/notes/375849 (SAP Service marketplace login required)
Key words : 
additional key words kks1, static assembly processing, production elements generated, symptom performance problems, attached advance correction, production memo, deviation recording, mass processings, sales order, deletion flag
Related Notes : 
       
| 540834 | FAQ: Order archiving (PP_ORDER and PR_ORDER) | 
| 309580 | Productn memo does not come from contract rel.order |