Note: For additional ORA-600 related information please read Note 146580.1

PURPOSE:
            
  This article discusses the internal error "ORA-600 [2103]", what 
  it means and possible actions. The information here is only applicable 
  to the versions listed and is provided only for guidance.
 
ERROR:              
  ORA-600 [2103] [a] [b] [c] [d]
 
VERSIONS:
  versions 6.0 to 11
 
DESCRIPTION:

  Oracle is attempting to acquire an enqueue.

  If this operation times out, an ORA-600 [2103] error is reported. 

  There are three formats of this error depending on Oracle release and 
  operation. Each format is identified by the number of additional
  arguments.

  Prior to Oracle Server release 7.3.4 (one additional argument)
  ------------------------------------------------------

  ORA-600 [2103] [a]

  Meaning:   Oracle has waited too long for the control file enqueue.

  ARGUMENTS:

  Arg [a] Time out - the time waited for the enqueue, in seconds.
                     (normally 900 seconds ie 15 Minutes)

  From Oracle 7.3.4 to 9.2 and above (4 additional arguments)
  --------------------------------------------------------

  ORA-600 [2103] [a] [b] [c] [d]

  Meaning:   Oracle has waited too long for the control file enqueue.
             This error has the same meaning as the single argument 
             case above - we simply output additional information.

  ARGUMENTS:

  Arg [a] 1-2 (Read only indicator - 0 for updates, 1 for read only, 2-rac/ops)
  Arg [b] 0 (Type indicator - 0 and 4 for ENQUEUE)
  Arg [c] 1 (Wait indicator - 1 indicates we should wait for the request)
  Arg [d] Time out - the time waited for the enqueue, in seconds.
                     (normally 900 seconds ie 15 Minutes)

  Oracle Server Release 9.0 and above
  -----------------------------------

  ORA-600 [a] [b]

  Meaning:   Oracle is trying to write a Checkpoint Progress record and has 
             waited too long for the enqueue.

  ARGUMENTS:

  ORA-600 [a] [b]
  ---------------

  Arg [a]   1 (Wait indicator - 1 indicates we should wait for the request)
  Arg [b] 256 (indicates we skip to the front of the convert queue)

FUNCTIONALITY:      
  CONTROL FILE MANAGEMENT COMPONENT
 
IMPACT:             
  Possible Instance Failure
 
SUGGESTIONS:        

  Check the alert log to see how often a logfile switch is taking place.

  Try and ensure that REDO log files are sized such that a log switch 
  takes place approximately every half hour during heavy load. This will 
  reduce the number of times we need to obtain the control file enqueue.
   
  Tune your datafile layout to resolve I/O contention.
  a. Determine if async IO is in use in any form.
  b. Determine if multiple DB writers in use.
     >> If BOTH async and multiple DB writers back one out.
     >> If just AsyncIO turn this OFF using the relevant init.ora parameter
           as this usually seems to occur with async IO.
     >> If multiple DB writers back down to 1 db writer 
 
  Check with the Hardware vendor to ensure there are no hardware problems
  and that you are on the latest OS patch level. 

  In the case of IBM, see Note 1058194.6 to obtain the correct OS 
  patch.

  Known issues:

  Bug# 6267208   See Note 6267208.8
      OERI:2103 due to deadlock between PV enqueue and "slave class create" latch
      Fixed: 10.2.0.4
 
  Bug# 6144079   See Note 6144079.8
      Instance crash in RAC (OERI:2103)
      Fixed: 10.2.0.4, 11.1.0.7, 11.2
 
  Bug# 5923866   See Note 5923866.8
      OERI[2103] when database is suspended
      Fixed: 10.2.0.4, 11.1.0.6
 
  Bug# 5526987 *  See Note 5526987.8
    * This bug is alerted in Note 468572.1
      ASM instance hang / OERI [2103] on DB instance
      Fixed: 10.2.0.4, 11.1.0.6, 10.2.0.3.P11
 
  Bug# 5134663   See Note 5134663.8
      OERI[2103] with ASM
      Fixed: 10.2.0.3, 11.1.0.6
 
  Bug# 5081798 +  See Note 5081798.8
      Additional diagnostics for OERI[2103] when ASM involved
      Fixed: 10.2.0.4, 11.1.0.6, 10.2.0.3.P11
 
  Bug# 5011019   See Note 5011019.8
      OERI[2103] on bystander standby during target standby failover
      Fixed: 10.2.0.3, 11.1.0.6
 
  Bug# 4671216   See Note 4671216.8
      ASM operations on a file are blocked while it is resized
      Fixed: 10.2.0.2, 11.1.0.6, 10.2.0.1.P05, 10.1.0.5.P03
 
  Bug# 4348230   See Note 4348230.8
      OERI:2103 should try to remove the blocking session
      Fixed: 10.1.0.5, 10.2.0.2, 11.1.0.6
 
  Bug# 4164021   See Note 4164021.8
      OERI [2103] during BACKUP CONTROLFILE to TRACE
      Fixed: 9.2.0.8, 10.1.0.5, 10.2.0.2, 11.1.0.6
 
  Bug# 3724485   See Note 3724485.8
      Enqueue waits may occur with no obvious holder in RAC
      Fixed: 9.2.0.6, 10.1.0.4, 10.2.0.1
 
  Bug# 3675033   See Note 3675033.8
      Reintroduction of RAC instance can result in hang / OERI:2103
      Fixed: 9.2.0.6, 10.2.0.1
 
  Bug# 3400979   See Note 3400979.8
      Dump of FILE_HDRS may hang or error (can result in OERI [2103])
      Fixed: 9.2.0.6, 10.1.0.4, 10.2.0.1
 
  Bug# 3030298   See Note 3030298.8
      OERI:2103 from concurrent 'drop tablespace including datafiles'
      Fixed: 9.2.0.5, 10.1.0.2
 
  Bug# 2952096   See Note 2952096.8
      Poor performance / OERI:2103 possible in RAC with mirrors and volume manager
      Fixed: 9.2.0.5, 10.1.0.2
 
  Bug# 2950375   See Note 2950375.8
      OERI[2103] in RAC if LMD0 is producing a dump
      Fixed: 9.2.0.4, 10.1.0.2
 
  Bug# 2872299   See Note 2872299.8
      OERI:2103 / instance crash can occur if foreground hits data/index internal error
      Fixed: 9.2.0.4, 10.1.0.2
 
  Bug# 2843570   See Note 2843570.8
      OERI:2103 possible on PRIMARY if secondary errors
      Fixed: 9.2.0.4, 10.1.0.2
 
  Bug# 1746869   See Note 1746869.8
      OERI:2103 possible during reconfiguration
      Fixed: 9.0.1.3, 9.2.0.1
 
  Bug# 1223914   See Note 1223914.8
      OERI:2103 possible using concurrent ALTER TABLESPACE READ ONLY/WRITE
      Fixed: 8.1.6.3, 8.1.7.0
 
  Bug# 719498   See Note 719498.8
      Backup CONTROLFILE to trace could crash DB with OERI:2103
      Fixed: 8.0.5.2, 8.0.6.0