How to Resolve ORA-00020 Error in Oracle Database

If we got this error in alert log file we increased the number of process parameter, Oracle default value of process is 300. we can increase the process as per requirement when we setup the database.

Once this error is generated, we are not able to log in to the database. To increase the value of Process, we follow the following steps:

1. Connected to database with this prelim option.

sqlplus -prelim / as sysdba

2. Verify the maximum value of resources utilization from following query.
Note: It will help to analyzed how maximum utilization is going.

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

3. Check the values of parameters process, session, and transaction.

show parameter processes
show parameter sessions
show parameter transactions

Note: Oracle use following formula for the setting parameters:
processes=x
sessions=x*1.1+5
transactions=sessions*1.1

4. Increase the value of process parameter with following command.

alter system set processes=300 scope=spfile;

5. Shutdown and startup the database

shutdown immediate
startup

Note: Check the value of parameters again, it will automatically increase the value of other parameter according to above formula.