ORA-00020: maximum number of processes (%s) exceeded

Problem

The issue is due to process/sessions parameter exceeds the limit. Need to increase those parameter to solve this issue.


Solution

When ORA-00020 occurred then you wont able to  connect to the DB via sys user to change the parameter. You can use following steps to overcome the issue.

1. Login to DB using following command

[oracle@prod 11.1.0]$ sqlplus -prelim "/ as sysdba"

2. Shutdown the DB

SQL>shutdown abort;

3. Exit from session

SQL>exit;

4. Connect to DB via sys

[oracle@prod 11.1.0]$ sqlplus / as sysdba

5. Start the DB

SQL>startup;

6. Check the Value for Process and sessions parameter

SQL>select resource_name, current_utilization, max_utilization, limit_value from v$resource_limit where resource_name in ('sessions', 'processes');

7. Change the Parameter values

SQL> alter system set processes=300 scope=spfile;
SQL> alter system set sessions=500 scope=spfile;