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

PURPOSE:            
  This article discusses the internal error "ORA-600 [2662]", 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 [2662] [a] [b] [c] [d] [e]
 
VERSIONS:
  versions 6.0 to 10.1
 
DESCRIPTION:

  A data block SCN is ahead of the current SCN.

  The ORA-600 [2662] occurs when an SCN is compared to the dependent SCN 
  stored in a UGA variable.

  If the SCN is less than the dependent SCN then we signal the ORA-600 [2662]
  internal error.

ARGUMENTS:
  Arg [a]  Current SCN WRAP
  Arg [b]  Current SCN BASE
  Arg [c]  dependent SCN WRAP
  Arg [d]  dependent SCN BASE 
  Arg [e]  Where present this is the DBA where the dependent SCN came from.
 
FUNCTIONALITY:      
  File and IO buffer management for redo logs
 
IMPACT:
  INSTANCE FAILURE
  POSSIBLE PHYSICAL CORRUPTION
 
SUGGESTIONS:        
     
  There are different situations where ORA-600 [2662] can be raised.

  It can be raised on startup or duing database operation.

  If not using Parallel Server, check that 2 instances have not mounted
  the same database.

  Check for SMON traces and have the alert.log and trace files ready
  to send to support.

  Check the SCN difference [argument d]-[argument b].

  If the SCNs in the error are very close, then try to shutdown and startup
  the instance several times. 

  In some situations, the SCN increment during startup may permit the 
  database to open. Keep track of the number of times you attempted a 
  startup.

  If the Known Issues section below does not help in terms of identifying
  a solution, please submit the trace files and alert.log to Oracle
  Support Services for further analysis.
 
  Known Issues:
  Bug# 4453449   See Note 4453449.8
      OERI:3020 / corruption errors from multiple FLASHBACK DATABASE
      Fixed: 10.2.0.2, 11
 
  Bug# 2899477   See Note 2899477.8
      Minimise risk of a false OERI[2662]
      Fixed: 9.2.0.5, 10.1.0.2
 
  Bug# 2764106   See Note 2764106.8
      False OERI[2662] possible on SELECT which can crash the instance
      Fixed: 9.2.0.5, 10.1.0.2
 
  Bug# 2216823   See Note 2216823.8
      OERI [2662] reusing a TEMPFILE with a restored database
      Fixed: 10.1.0.2
 
  Bug# 2054025   See Note 2054025.8
      OERI:2662 possible on new TEMPORARY index block
      Fixed: 9.0.1.3, 9.2.0.1
 
  Bug# 851959   See Note 851959.8
      OERI:2662 possible from distributed OPS select
      Fixed: 7.3.4.5
 
  Bug# 647927 P  See Note 647927.8
      Digital Unix ONLY: OERI:2662 could occur under heavy load
      Fixed: 8.0.4.2, 8.0.5.0