Dropping connected users in Oracle database

Question

I want to drop some users in Oracle DB using sqlplus but I am getting error:

SQL> DROP USER test CASCADE;
DROP USER test CASCADE
*
ERROR at line 1:
ORA-01         


        

Answer 1

Basically I believe that killing all sessions should be the solution, but...

I found similar discussion - https://community.oracle.com/thread/1054062 to my problem and that was I had no sessions for that users, but I still received the error. I tried also second the best answer:

sql>Shutdown immediate;

sql>startup restrict;

sql>drop user TEST cascade;

What worked for me at the end was to login as the user, drop all tables manually - select for creating drop statements is

select 'drop table ' || TABLE_NAME || ';'  from user_tables;

(Needs to be re-run several times because of references)

I have no idea how is that related, I dropped also functions and sequences (because that was all I had in schema)

When I did that and I logged off, I had several sessions in v$session table and when I killed those I was able to drop user.

My DB was still started in restricted mode (not sure if important or not).

Might help someone else.

BTW: my Oracle version is Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production

Answer 2

Here's how I "automate" Dropping connected users in Oracle database:

# A shell script to Drop a Database Schema, forcing off any Connected Sessions (for example, before an Import) 
# Warning! With great power comes great responsibility.
# It is often advisable to take an Export before Dropping a Schema

if [ "$1" = "" ] 
then
    echo "Which Schema?"
    read schema
else
    echo "Are you sure? (y/n)"
    read reply
    [ ! $reply = y ] && return 1
    schema=$1
fi

sqlplus / as sysdba <<EOF
set echo on
alter user $schema account lock;
-- Exterminate all sessions!
begin     
  for x in ( select sid, serial# from v\$session where username=upper('$schema') )
  loop  
   execute immediate ( 'alter system kill session '''|| x.Sid || ',' || x.Serial# || ''' immediate' );  
  end loop;  
  dbms_lock.sleep( seconds => 2 ); -- Prevent ORA-01940: cannot drop a user that is currently connected
end;
/
drop user $schema cascade;
quit
EOF

Answer 3

I had the same problem, Oracle config in default affects letter register. In exact my Scheme_Name was written all Capital letters. You can see your Scheme_Name on "Other Users" tab, if you are using Oracle S

Answer 4

Issue has been fixed using below procedure :

DECLARE
  v_user_exists NUMBER;
  user_name CONSTANT varchar2(20) := 'SCOTT';
BEGIN
  LOOP
    FOR c IN (SELECT s.sid, s.serial# FROM v$session s WHERE upper(s.username) = user_name)
    LOOP
      EXECUTE IMMEDIATE
        'alter system kill session ''' || c.sid || ',' || c.serial# || ''' IMMEDIATE';
    END LOOP;
    BEGIN
      EXECUTE IMMEDIATE 'drop user ' || user_name || ' cascade';
      EXCEPTION WHEN OTHERS THEN
      IF (SQLCODE = -1940) THEN
        NULL;
      ELSE
        RAISE;
      END IF;
    END;
    BEGIN
      SELECT COUNT(*) INTO v_user_exists FROM dba_users WHERE username = user_name;
      EXIT WHEN v_user_exists = 0;
    END;
  END LOOP;
END;
/

Answer 5

If you use RAC then you need to use GV$* views instead V$*. Try to find your session by

select * from gv$session where username = 'test';

and then you can kill the session by

alter system kill session 'sid, serial#, @inst_id' immediate;

Answer 6

Sometimes Oracle drop user takes long time to execute. In that case user might be connected to the database. Better you can kill user session and drop the user.

SQL> select 'alter system kill session ''' || sid || ',' || serial# || ''' immediate;' from v$session where username ='&USERNAME';

SQL> DROP USER barbie CASCADE;