Solution : https://service.sap.com/sap/support/notes/126637 (SAP Service marketplace login required)
Key words : 
additional key words vl01, attached advance corrections, sales document takes, document files, direct processing, subsequent processing, large number, schedule lines, performance improvements, prerequisites
Related Notes : 
       
| 154091 | Performance in delivery process: Collective note | 
| 131772 | Performance when creating delivery (SELECT VEPVG) | 
| 113040 | Performance of sales document processing |