0020: maximum number of processes (1000) exceeded

This error will not allow to login to the database. So firstly shut down any applications that connect to the particular database.

Then it will allow to log in to  the database.

SQL> select count(*) from v$process;

  COUNT(*)
----------
    27

 SQL> show parameter processes

 processes                 integer     1000

Now parameter process are set to 1000

To increase the parameters 

SQL> alter system set processes=3000 scope=spfile;

Shutdown the database.

 

SQL> shutdown immediate

Database closed. 

Database dismounted. 

ORACLE instance shut down. 

Then start the database

 

 SQL> startup ORACLE instance started. 

Verify the changes

 SQL> show parameter processes 

NAME                                   TYPE           VALUE

 ------------------------------------ -----------      ------------------------------ 

processes                             integer      3000