How to increase the number of processes allowed in oracle database.

Log in as sys

$ sqlplus sys as sysdba;

Enter the passed for sys when prompted.

If your application makes many connections and the number of processes allowed to be created by the oracle db is smaller than that, you will get the error

ORA-12519: TNS:no appropriate service handler found

To solve this issue, first view the number of processes allowed by oracle.

SQL> select * from v$resource_limit where resource_name = 'processes';

If you are using oracle express edition, this value would be 40.

Now increase number of allowed the processes

SQL>alter system set processes=300 scope=spfile;
SQL>shutdown immediate;
SQL>startup