Solution : https://service.sap.com/sap/support/notes/1148494 (SAP Service marketplace login required)
Key words : 
memory consumption suddenly increases, database analyzer parameter check, terms memory consumption, reserved memory area, database server, parameter hashed_resultset, system downtime, system heap, maxdb version 7, bi environment
Related Notes : 
       
| 814704 | MaxDB Version 7.6 parameter settings for OLTP/BW |