Solution : https://service.sap.com/sap/support/notes/1144394 (SAP Service marketplace login required)
Key words : 
file'/usr/spool/sql/ini/sap_dbtech, wrong permissionthe operating system user, -windows operating systems, sapdb database fails, maxdb version higher, software upgrade makes, 31_extthis error occurs, sql error -888, terms sap_dbtech, ini' solution
Related Notes : 
       
| 1537945 | sqlcode=-888 (Could not load libpcr ...) | 
| 1353266 | Additional information about MaxDB version upgrade to 7.8 | 
| 1004973 | Additions to MaxDB version upgrade to 7.7 | 
| 793550 | Supplementary info about the MaxDB version upgrade to 7.6 | 
| 669711 | Additional information about MaxDB upgrade to 7.5.00 |