Friday, September 28, 2012

What causes ORA-03135? (part 1)

This was tested on Oracle 11.2. I wanted to understand what might cause an ORA-03135. First I connected as a normal user:
 
SQL> conn andrew/reid
Connected.
SQL>
 
Then , in another session, I identified its UNIX process id:
 
SQL> conn / as sysdba
Connected.
SQL> select username, paddr
  2  from v$session
  3  where username = 'ANDREW'
  4  /
 
USERNAME                       PADDR
------------------------------ ----------------
ANDREW                         00000003A4B686C0
 
SQL> select spid from v$process
  2  where addr = '00000003A4B686C0'
  3  /
 
SPID
------------------------
15733
 
SQL>
 
Next I killed that process:
 
Solaris > kill -9 15733
Solaris >
 
... and when I returned to the first session and ran a select sysdate from dual, I got an ORA-03135:
 
SQL> conn andrew/reid
Connected.
SQL> select sysdate from dual;
select sysdate from dual
*
ERROR at line 1:
ORA-03135: connection lost contact
Process ID: 15733
Session ID: 394 Serial number: 7099
 
SQL>
 
So, one possible cause of an ORA-03135 is that something has caused your session’s underlying OS process to die.

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