Problem with Log Writer

Question

Hi,
I got the alert from OEM that 1 session is blocking another 3 sessions. When i came to know what is that session, i found that the blocking session is caused by LGWR, it is blocking other 3 sessions.
How can i avoid the session which is caused by LGWR, to avoid the blocking of other sessions.
Thanks,
Mahi

Answer 1

I have never heard of log wirter locking user sessions, I suggest you use the following SQL next time you see this problem to identify lokers and lock waiters:
set feedback off
set echo off
set pause off
set linesize 110
column osuser format a15
column username format a15
column SCHEMANAME format a15
column COMMAND format a25
select 'lock waiter: ',s.sid,p.spid os_pid,s.PROCESS,s.status, s.osuser,s.username,
s.SCHEMANAME,s.COMMAND,
s.MACHINE,s.MODULE,s.SERIAL#, s.LOCKWAIT,s.action, s.type
from v$session s, v$process p
WHERE s.paddr = p.addr
and s.lockwait is not null
order by 4;
select 'locker: ',s.sid,p.spid os_pid,s.PROCESS,s.status, s.osuser,s.username,
s.SCHEMANAME,s.COMMAND,
s.MACHINE,s.MODULE,s.SERIAL#, s.LOCKWAIT,s.action, s.type
from v$session s, v$process p
WHERE s.paddr = p.addr
and s.sid in
(select SESSION_ID from DBA_LOCKS
where BLOCKING_OTHERS <> 'Not Blocking')
order by 4;
spool off
Bobby A.
Edited by: babak akbari on May 8, 2009 2:06 PM