/usr/local/Enterasys_Networks/NetSight/mysql/bin/mysql -S /tmp/netsight_mysql.sock -u netsight -p
"root" will not have access to the db. Check the "Netsight Suite wide Tools User Guide" (Section 'Managing the Database') for the default password. However, I am not an expert considering the NS db and found that setting only by best guess. I don't know if changing it will suffice to solve your problem. If you are not forced to take desperate measures, I'd rather advise to contact support.