View and modify connections in Oracle

Number of connections in Oracle 1. query the number of connections of the current process in the database: www.2cto.com select count (*) from v $ process; 2. view the number of connections to the current session of the database: elect count (*) from v $ session; 3. view the number of concurrent connections of the database: www.2cto.com select count (*) from v $ session where status = 'active'; 4. view the Sessions established by the current database: select sid, serial #, username, program, machine, status from v $ session; 5. query the maximum number of connections allowed by the database: select value from v $ parameter where name = 'processs'; or command: show parameter processes; 6. number of changes Maximum number of connections allowed by the database: alter system set processes = 300 scope = spfile; (you need to restart the database to modify the number of connections) restart the database: SQL> shutdown immediate; SQL> startup; check which users are using data: SQL> select osuser,. username, cpu_time/executions/1000000 |'s, SQL _fulltext, machine SQL> from v $ session a, v $ sqlarea B SQL> where. SQL _address = B. address SQL> order by cpu_time/executions desc; Note: one session of a UNIX user corresponds to an operating system process, while Windows is embodied in a thread. Start oracle su-oracle SQL> sqlplus system/pwd as sysdba // enter SQL SQL> startup // start Database SQL> lsnrctl start // start listening sqlplus "/as sysdba" SQL> shutdown immediate; // close database SQL> startup mount; SQL> alter database open;