Solution : https://service.sap.com/sap/support/notes/812709 (SAP Service marketplace login required)
Key words : 
read798363 snp-bf     initialization ignores parallel processing profile742563 fcs-bf     /sapapo/ts_parea_initialize, snp low-level code777455 bc-db-lca  scm 4, products854233 bc-db-lca  increasing memory requirement, deleting time series844557 ppc-heu    unnecessary reading, detail view730495 snp-bf     model consistency check, long runtime708529 snp-bf     snp initialization creates, low-level code determination687808 snp-ins, save database key figures729512 snp        information, snp planning area843585 fcss    version copy, snp heuristics856904 snp-mac    performance improvement
Related Notes : 
       
| 766827 | Composite SAP note: Performance SCM 4.0 | 
| 753137 | Composite SAP note: Performance in SNP for SCM 4.0 | 
| 548832 | SNP Performance for 3.10 | 
| 420599 | Composite SAP Note: Performance of SNP 3.0A |