Handling blocking sessions

Check blocking sessions

select l1.sid, ' IS BLOCKING ', l2.sid
from v$lock l1, v$lock l2
where l1.block =1 and l2.request > 0
and l1.id1=l2.id1;


select s1.username || '@' || s1.machine
|| ' ( SID=' || s1.sid || ' )  is blocking '
|| s2.username || '@' || s2.machine || ' ( SID=' || s2.sid || ' ) ' AS blocking_status
from v$lock l1, v$session s1, v$lock l2, v$session s2
where s1.sid=l1.sid and s2.sid=l2.sid
and l1.BLOCK=1 and l2.request > 0
and l1.id1 = l2.id1
and l2.id2 = l2.id2;

View sessions details

select sid,
       to_char(logon_time,'MMDDYYYY:HH24:MI') logon_time,  username,
       type, status, process, sql_address, sql_hash_value
  from v$session
where username is not null and sid = &sid_no and serial#=&serial_no;

Kill blocking session

alter system kill session '&SID,&SERIAL ';
or
ALTER SYSTEM DISCONNECT SESSION '&SID,&SERIAL' IMMEDIATE;