PROBLEM:

While connecting to the database, getting error:

SQL> connect test9/test9
ERROR:
ORA-02391: exceeded simultaneous SESSIONS_PER_USER limit

SOLUTION:

1. Check how many sessions were already existed for that user:

SELECT count(*) as connections,username FROM v$session where username=’&USER_NAME’ GROUP BY username;

TEST9 user has currently 2 sessions.

2. Check the value of SESSIONS_PER_USER for this user

col username for a12
col profile for a19
col limit for a12
set lines 299
select a.username,b.PROFILE,b.RESOURCE_NAME,b.limit from dba_users a , dba_profiles b where a.profile=b.profile and b.RESOURCE_NAME=’SESSIONS_PER_USER’ and a.username=’&USER_NAME’;

We can see, the sessions_per_user allowed for this users in 2. To fix this user, increase the limit for SESSIONS_PER_USER in the profile.

Here the profile for the user is TEST

3. Alter the profile with higher SESSIONS_PER_USER value.

Now try to connect with the user.