Solution : https://service.sap.com/sap/support/notes/421419 (SAP Service marketplace login required)
Key words : 
object                            valuerepeat_enqueue_md_update_00001     0infoobject1repeat_enqueue_md_update_00002     0infoobject2, repeat_enqueue_md_update_count     8repeat_enqueue_md_update_wait      100this solution, 0b            import support package 17, 1c            import support package 09, long runtime reason, extract disjunct amounts, function module rsa2_rsadmin_put, 0b support package 17, 1c support package 09, terms parallel loading
Related Notes : 
       
| 567747 | Composite note BW 3.x performance: Extraction & loading |