How can I view the current number of connections in Oracle? You only need to use the following SQL statement to query it.

How can I view the current number of connections in Oracle? You only need to use the following SQL statement to query it.

Select * from V $ session where username is not null

Select username, count (username) from V $ session where username is not null group by username # view the number of connections of different users

Select count (*) from V $ session # Number of connections

Select count (*) from V $ session where status = 'active' # number of concurrent connections

Show parameter Processes # maximum connection

Alter system set processes = value scope = spfile; restart database # modify connection

1. Check the current session count, processes, and sessions values, and find that the number of sessions and the values of the two parameters are very close.

SQL> Conn/As sysdba is connected.

SQL> select count (*) from V $ session;

SQL> show parameter processes;

SQL> show parameter sessions;

2. Modify the values of processes and sessions

SQL> alter system set processes = 300 scope = spfile;

The system has been changed.

SQL> alter system set sessions = 300 scope = spfile;

The system has been changed.

 

3. View the processes and sessions parameters, but the changes do not take effect.

 

4. Restart the database for the change to take effect

SQL> shutdown immediate

SQL> startup

SQL> show parameter Processes
SQL> show parameter sessions

 

 

 

Query the data that is connected to the database

Select v. machine,
V. username,
V. paddr,
V. osuser,
V. program,
V. logon_time,
V. Status
From v $ Session V
Where v. username is not null
Order by V. logon_time DESC;

Select count (*)
From v $ Session V
Where v. username is not null
Order by V. logon_time DESC;