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

• Purpose of ORA-00020 is because of  to-many database connections which exceeds your processes parameter. Which will stop your running transactions and no users can connect.

• In a production environment neither we can tell the users to stop the transactions nor we can kill their sessions.You can kill their sessions if users are not working (idle sessions)

• Take Down time from the users.

• Shutdown the Application and Bounce your Cluster database.

SQL> Alter system set processes=1000 scope=spfile sid='*';

D:\app\oracle> srvctl stop database -d hrlive

D:\app\oracle> srvctl start database -d hrlive

D:\app\oracle> sqlplus / as sysdba

SQL> show parameter processes;

NAME                     TYPE           VALUE

---------------------------------------------
aq_tm_processes         integer           1
cell_offload_processing boolean          TRUE
db_writer_processes     integer           3
gcs_server_processes    integer           2
global_txn_processes    integer           1
job_queue_processes     integer          1000
log_archive_max_proceses integer          4
processes                integer         1000
processor_group_name     string

• Start the Application

Note:-  Use  sqlplus -perlim "/as sysdba" if you are not able to connect.

Happy Learning.....