Thinking Out Loud

May 14, 2021

Gather Your Session Info For Killing

Filed under: 11g,linux,oracle — mdinh @ 4:40 am

So there I was, running emremove.sql as part of pre-upgrade task; however, it was taking longer than expected.

Session was stuck at the output shown below and desperately CTRL-C did not work.

14:35:05 472  /
old  70:     IF (upper('&LOGGING') = 'VERBOSE')
new  70:     IF (upper('VERBOSE') = 'VERBOSE')

^C

^C^C

^C

I checked for blocking session and there were blocking locks from SYS which was really strange.

I made a gutsy call and kill SYS session from OS prompt based on timestamp.

~ $ ps -ef|grep sysdba
oracle    57147 231962  0 May12 pts/4    00:00:00 sqlplus   as sysdba
oracle   155919 139352  0 14:34 pts/1    00:00:00 sqlplus   as sysdba
oracle   244619 216760  0 15:25 pts/5    00:00:00 grep --color=auto sysdba

~ $ kill -9 155919

As it turns out, another DBA was logged in as sysdba causing havoc.

I was lucky to have killed the correct SYS session and will you be as lucky as I was?

Based on my near disaster, it would be better to create good practice of gathering your session info to be able to kill the correct session.

Here is current session info.

SQL> @my
SQL> select b.sid, b.serial#, a.spid processid, b.process clientpid from v$process a, v$session b
  2  where a.addr = b.paddr
  3  and b.audsid = userenv('sessionid')
  4  and b.sid=userenv('sid')
  5  ;

       SID    SERIAL# PROCESSID                CLIENTPID
---------- ---------- ------------------------ ------------------------
         5        101 16428                    16427

SQL>

[oracle@ol7-112-dg1 ~]$ ps -ef|grep 16427
oracle   16427  8573  0 03:44 pts/0    00:00:00 sqlplus   as sysdba
oracle   16428 16427  0 03:44 ?        00:00:00 oraclehawk (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq)))
oracle   16461 11677  0 03:45 pts/1    00:00:00 grep --color=auto 16427
[oracle@ol7-112-dg1 ~]$

Kill OS process using sqlplus PROCESSID – don’t know session is killed until DML is performed.

[oracle@ol7-112-dg1 ~]$ kill -9 16428

SQL> select * from dual;
select * from dual
*
ERROR at line 1:
ORA-03135: connection lost contact
Process ID: 16428
Session ID: 5 Serial number: 101


SQL>

Another test

--- Session Info
SQL> @my
SQL> select b.sid, b.serial#, a.spid processid, b.process clientpid from v$process a, v$session b
  2  where a.addr = b.paddr
  3  and b.audsid = userenv('sessionid')
  4  and b.sid=userenv('sid')
  5  ;

       SID    SERIAL# PROCESSID                CLIENTPID
---------- ---------- ------------------------ ------------------------
         5        103 16533                    16532

SQL>

--- From another session, check waits for above session
SQL> r
  1  select NVL(s.username,'(oracle)') AS username, s.sid, s.serial#,
  2  sw.event, sw.seconds_in_wait, sw.state
  3  from v$session_wait sw, v$session s
  4  where s.sid = sw.sid and s.sid=&sid
  5*
Enter value for sid: 5
old   4: where s.sid = sw.sid and s.sid=&sid
new   4: where s.sid = sw.sid and s.sid=5

USERNAME               SID    SERIAL# EVENT                          SECONDS_IN_WAIT STATE
--------------- ---------- ---------- ------------------------------ --------------- -------------------
SYS                      5        115 SQL*Net message from client                169 WAITING

SQL>

Kill OS process using sqlplus CLIENTPID – immediate feedback –

[oracle@ol7-112-dg1 ~]$ ps -ef|grep 16532
oracle   16532  8573  0 03:46 pts/0    00:00:00 sqlplus   as sysdba
oracle   16533 16532  0 03:46 ?        00:00:00 oraclehawk (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq)))
oracle   16557 11677  0 03:47 pts/1    00:00:00 grep --color=auto 16532
[oracle@ol7-112-dg1 ~]$


[oracle@ol7-112-dg1 ~]$ kill -9 16532


SQL> Killed
[oracle@ol7-112-dg1 ~]$

Hopefully you will never have to kill your own session.

When you need kill your session, it’s better to have the correct information versus guessing.

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