Solution : https://service.sap.com/sap/support/notes/1378344 (SAP Service marketplace login required)
Key words : 
symptom performance improvement, attached correction instruction, terms check, program error, solution implement, support package, prerequisites
Related Notes : 
       
| 1378291 | Performance Improvement in PO History | 
| 1266771 | SRM 7.0 Performance Guide |