Solution : https://service.sap.com/sap/support/notes/1068950 (SAP Service marketplace login required)
Key words : 
kb stack type illegal, indexparallel index access solution, system issues error message -9211, parallel index processing, system error, parallel join, parameter optimize_join_parallel_servers, execution plan, indexed columnaddnl, terms -9211
Related Notes : 
       
| 814704 | MaxDB Version 7.6 parameter settings for OLTP/BW |