Solution : https://service.sap.com/sap/support/notes/886266 (SAP Service marketplace login required)
Key words : 
/os v8 zparm system parameter locking reason, db2 v8 apar pq98172 introduces, deletes acquire strong locks, system parameter xlkupdlt, strong locking semantics, db2 setting xlkupdlt =, strong lock acquisition, reduces locking, xlkupdlt = target, set xlkupdlt =
Related Notes : 
       
| 728743 | Series z: Release of DB2 V8 for SAP Components | 
| 717215 | DB2-z/OS: DB2 V8 configuration for SAP rel. <= 4.6D |