Amerjit
SAP is still investigating to find out the root cause of the issue. Unfortunately there is no solution yet except restoring the database. They suggested to restore the HANA DB to a previous backup from a working condition. I did that and now the system is back. But the issue with High Memory usage still pending and waiting from SAP to fix that issue.
Have learned few lessons from this Upgrade and going to implement them during next one. I will update the blog once we have a solution from SAP.
Mahesh Shetty