ORA-00018 maximum number of sessions exceeded

ORA-00018 maximum number of sessions exceeded

Cause: All session state objects are in use.

Action: Increase the value of the SESSIONS initialization parameter.

ORA-00018 comes under "Oracle Database Server Messages". These messages are generated by the Oracle database server when running any Oracle program.

How to increase SESSION initialization parameter:

1. Login as sysdba

 sqlplus / as sysdba

2. Check Current Setting of Parameters

 sql> show parameter sessions

 sql> show parameter processes

 sql> show parameter transactions

3. If you are planning to increase "sessions" parameter you should also plan to increase "processes and "transactions" parameters.

A basic formula for determining  these parameter values is as follows:

  processes=x

  sessions=x*1.1+5

  transactions=sessions*1.1

4. These paramters can't be modified in memory. You have to modify the spfile only (scope=spfile) and bounce the instance.

 sql> alter system set processes=500 scope=spfile;

 sql> alter system set sessions=555 scope=spfile;

 sql> alter system set transactions=610 scope=spfile;

 sql> shutdown abort

 sql> startup