Solution : https://service.sap.com/sap/support/notes/563359 (SAP Service marketplace login required)
Key words : 
sqlplus sap<sid>/<password>@<sid>, user ora<sid>, user sap<sid>, lob data types, sql script lobcacheon, sql script lobcacheoff, zip       /oracle/oracle, symptom performance optimization, sap system, sap marketplace
Related Notes : 
       
| 1476753 | NetWeaver BPM: Performance issues on Oracle Database | 
| 983230 | LOB corruption for NOCACHE LOBs in ASSM (ORA-1555/ORA-22924) | 
| 889038 | Collective note: NWDI server component configuration | 
| 871096 | Oracle 10.2.0: Patches/patch collections for Oracle 10.2.0.2 | 
| 848708 | Oracle Database Configuration for NWDI server | 
| 793113 | FAQ: Oracle I/O configuration | 
| 766349 | FAQ: Oracle SQL optimization | 
| 692646 | Performance Content Integrator | 
| 619188 | FAQ: Oracle wait events | 
| 354080 | Note collection for Oracle performance problems |