ORA-01919: role 'PLUSTRACE' does not exist

SYS@orcl> grant PLUSTRACE to jingyu;
grant PLUSTRACE to jingyu
      *
ERROR at line 1:
ORA-01919: role 'PLUSTRACE' does not exist

SYS@orcl> @?/sqlplus/admin/plustrce.sql
SYS@orcl> 
SYS@orcl> drop role plustrace;
drop role plustrace
          *
ERROR at line 1:
ORA-01919: role 'PLUSTRACE' does not exist


SYS@orcl> create role plustrace;

Role created.

SYS@orcl> 
SYS@orcl> grant select on v_$sesstat to plustrace;

Grant succeeded.

SYS@orcl> grant select on v_$statname to plustrace;

Grant succeeded.

SYS@orcl> grant select on v_$mystat to plustrace;

Grant succeeded.

SYS@orcl> grant plustrace to dba with admin option;

Grant succeeded.

SYS@orcl> 
SYS@orcl> set echo off
SYS@orcl> 

SYS@orcl> grant PLUSTRACE to jingyu;

Grant succeeded.