select decode(request, 0, 'Holder: ', 'Waiter: ') || sid sess,
id1,
id2,
lmode,
request,
type
from v$lock
where (id1, id2, type) in
(select id1, id2, type from v$lock where request > 0)
order by id1, request;
select blocking_session, sid, wait_class, sql_id, seconds_in_wait
from v$session
where blocking_session is not NULL
order by blocking_session;
--To find the most important wait events in the last 15 minutes, issue the following query:
select session_id,
sql_id,
event,
sum(wait_time + time_waited) total_wait_time
from v$active_session_history
where sample_time between sysdate - 30 / 2880 and sysdate
group by event, session_id, sql_id
order by total_wait_time desc;
--You can identify the SQL statements that have been waiting the most during the last 15 minutes with this query.
select a.user_id,
u.username,
s.sql_text,
s.sql_id,
sum(a.wait_time + a.time_waited) total_wait_time
from v$active_session_history a, v$sqlarea s, dba_users u
where a.sample_time between sysdate - 30 / 2880 and sysdate
and a.sql_id = s.sql_id
and a.user_id = u.user_id
group by a.user_id, s.sql_text, u.username, s.sql_id
order by total_wait_time desc;
set echo off
col sid form 9999
col id1 form 9999999999
col id2 form 999999999
col lmode head "Lock Held" form a14
col request1 head "Lock Request" form a16
col type head "Lock Type" form a15
col ctime head "Time|Held" form 999999
col block head "No Of |Sessions|Waiting|For This|Lock" form 99999
---Check for Lock type, mode etc.
select sid,
DECODE(TYPE,
'BL','Buffer hash table',
'CF','Control File Transaction',
'CI','Cross Instance Call',
'CS','Control File Schema',
'CU','Bind Enqueue',
'DF','Data File',
'DL','Direct-loader index-creation',
'DM','Mount/startup db primary/secondary instance',
'DR','Distributed Recovery Process',
'DX','Distributed Transaction Entry',
'FI','SGA Open-File Information',
'FS','File Set',
'IN','Instance Number',
'IR','Instance Recovery Serialization',
'IS','Instance State',
'IV','Library Cache InValidation',
'JQ','Job Queue',
'KK','Redo Log "Kick"',
'LS','Log Start/Log Switch',
'MB','Master Buffer hash table',
'MM','Mount Definition',
'MR','Media Recovery',
'PF','Password File',
'PI','Parallel Slaves',
'PR','Process Startup',
'PS','Parallel Slaves Synchronization',
'RE','USE_ROW_ENQUEUE Enforcement',
'RT','Redo Thread',
'RW','Row Wait',
'SC','System Commit Number',
'SH','System Commit Number HWM',
'SM','SMON',
'SQ','Sequence Number',
'SR','Synchronized Replication',
'SS','Sort Segment',
'ST','Space Transaction',
'SV','Sequence Number Value',
'TA','Transaction Recovery',
'TD','DDL enqueue',
'TE','Extend-segment enqueue',
'TM','DML enqueue',
'TS','Temporary Segment',
'TT','Temporary Table',
'TX','Transaction',
'UL','User-defined Lock',
'UN','User Name',
'US','Undo Segment Serialization',
'WL','Being-written redo log instance',
'WS','Write-atomic-log-switch global enqueue',
'XA','Instance Attribute',
'XI','Instance Registration',
decode(substr(TYPE,1,1),
'L','Library Cache ('||substr(TYPE,2,1)||')',
'N','Library Cache Pin ('||substr(TYPE,2,1)||')',
'Q','Row Cache ('||substr(TYPE,2,1)||')',
'????')) TYPE,
id1,id2,
decode(lmode,
0,'None(0)',
1,'Null(1)',
2,'Row Share(2)',
3,'Row Exclu(3)',
4,'Share(4)',
5,'Share Row Ex(5)',
6,'Exclusive(6)') lmode,
decode(request,
0,'None(0)',
1,'Null(1)',
2,'Row Share(2)',
3,'Row Exclu(3)',
4,'Share(4)',
5,'Share Row Ex(5)',
6,'Exclusive(6)') request1,
ctime, block
from
v$lock
where sid>5
and type not in ('MR','RT')
order by decode(request,0,0,2),block,5
/
/
