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v$lock wait events

Oracle Tips by Burleson Consulting


The Oracle v$lock view lists all Oracle wait events and the dba_hist_enqueue_stat table.  Also see my lock notes:

The TYPE column in v$lock shows the type of wait events (listed in the script below), and we also have the LMODE column (lock mode) and REQUEST columns:

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',

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)')

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)')

Here is a comprehensive v$lock query by Deepak Baranwal, listing the lock types:

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

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
/

 

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