ORA-00020: maximum number of processes (1000) exceeded

Oracle database connection issue happen when number of processes exceeded.

Please find below for more detail in alert.log file.

 ORA-00020: maximum number of processes (1000) exceeded

 ORA-20 errors will not be written to the alert log for

 the next minute. Please look at trace files to see all

 the ORA-20 errors.

2020-02-04T04:48:11.688221-05:00

Process m000 submission failed with error = 20

Process m000 submission failed with error = 20

Process m000 submission failed with error = 20

2020-02-04T04:49:06.528563-05:00

ORA-00020: maximum number of processes (1000) exceeded

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

The ORA-00020 is a serious production error because a user cannot connect. 

The ORA-00020 is caused by two things:  

To fix this, use the 

SQL > ALTER SYSTEM KILL command.  

Execute following script in the Database.

alter system kill session '957,37560';

You may also need to kill session at the OS level with the KILL -9 

[oracle@ora ~]$ kill -9  

you can execute following script on Linux server.

kill -9 41158

kill -9 41563

Too few process buckets:  Oracle limits the number of connected processes with the processes parameter, and you may get the ORA-00020 error as the natural result in growth of system usage. 

Cause: 

All process state objects are in use.  

Action: 

Increase the value of the PROCESSES initialization parameter.

Check Current Setting of Parameters.

Execute following script in the Database.

    sql> show parameter sessions

    sql> show parameter processes

    sql> show parameter transactions

sql> alter system set processes=1500 scope=spfile;
sql> alter system set sessions=1555 scope=spfile;
sql> alter system set transactions=1610 scope=spfile;

Restart database after this operation as follows.

SQL> shutdown immediate

Database closed.

Database dismounted.

ORACLE instance shut down.

SQL>

SQL> startup

ORACLE instance started.

Total System Global Area 534462464 bytes

Fixed Size 2230072 bytes

Variable Size 339740872 bytes

Database Buffers 184549376 bytes

Redo Buffers 7942144 bytes

Database mounted.

Database opened.

SQL>