Oracle View the maximum number of connections and the current number of connections to see which users are currently using the data

Oracle View information such as the maximum number of connections
allowed and the current number of connections. After writing the program, it is helpful to analyze and optimize a robust system program by checking the release of the database connection while testing the code. 1. Sql code 1.select count(*) fromv$process  select count(*) from v$process where program='Oracle.EXE(SHAD)'; --The current number of database connections 2. Sql code 1.select value from v$parameter where name = 'processes' select value from v$parameter where name = 'processes'--the maximum number of connections allowed by the database 3. Sql code 1. alter system set processes = 300 scope =spfile; alter system set processes = 300 scope = spfile;--Modify the maximum number of connections: 4. Sql code 1.shutdown immediate; 



























2.startup;
shutdown immediate;
startup;--restart the database

5.
Sql code
1.SELECT osuser, a.username,cpu_time/executions/1000000||'s',b.sql_text,machine  
2.from v$session a, v$sqlareab 
3.where a.sql_address =b.address order by cpu_time/executionsdesc;
SELECT osuser, a.username,cpu_time/executions/1000000||'s',b.sql_text,machine
from v$session a, v$ sqlarea b
where a.sql_address =b.address order by cpu_time/executionsdesc; --Check
which users are currently using data

6.
Sql code
1.select count(*) fromv$session 
select count(*) from v$session - -The current number of session connections

7.
Sql code
1.select count(*) from v$session wherestatus='ACTIVE'
select count(*) from v$session where status='ACTIVE' -- number of concurrent connections

8.
Sql code
1.show parameterprocesses 
show parameter processes --maximum connections