View connections in Oracle

Sometimes the database can be connected, and sometimes the database cannot be connected.

It may be that the current number of connections in the database has exceeded the maximum number it can process.

 

Select count (*) from V $ process -- current number of connections
Select value from V $ parameter where name = 'processs' -- maximum number of connections allowed by the database

Modify the maximum number of connections:
Alter system set processses = 300 scope = spfile;

Restart the database:
Shutdown immediate;
Startup;

-- View which users are currently using data
Select osuser, A. username, cpu_time/executions/1000000 |'s ', SQL _fulltext, Machine
From v $ session A, V $ sqlarea B
Where a. SQL _address = B. Address order by cpu_time/executions DESC; select count (*) from V $ session # Number of connections

Select count (*) from V $ session where status = 'active' # concurrent connection count show parameter Processes # maximum connection alter system set processes = value scope = spfile; restart database # modify connection