查看当前License情况
SQL> show parameter license;
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
license_max_sessions integer 0
license_max_users integer 0
license_sessions_warning integer 0
查看Oracle的最大并发数限制，可是查看v$license视图
v$license视图：
里面记录了Oracle最大的并发数以及当前用户的连接数，
官方文档有如下描述：
This view contains information about license limits.
ColumnDatatypeDescriptionSESSIONS_MAX
NUMBER
Maximum number of concurrent user sessions allowed for the instance
SESSIONS_WARNING
NUMBER
Warning limit for concurrent user sessions for the instance
SESSIONS_CURRENT
NUMBER
Current number of concurrent user sessions
SESSIONS_HIGHWATER
NUMBER
Highest number of concurrent user sessions since the instance started
USERS_MAX
NUMBER
Maximum number of named users allowed for the database
其实，该试图中的SESSIONS_CURRENT就等于select count(*) from v$session where TYPE = 'USER'
show parameter license_max_sessions //查看最大并发数，如果是0，则默认是无限制，但如果在
在初始化文件里说明了，就以初始化文件为主