Last updated on DECEMBER 10, 2016
Applies to:Oracle Net Services - Version 126.96.36.199.0 to 188.8.131.52 [Release 8.1.7 to 11.2]
Oracle Database - Enterprise Edition - Version 184.108.40.206 to 220.127.116.11 [Release 8.1.7 to 11.2]
Information in this document applies to any platform.
This issue can occur in any version below 12.1 where DCD or SQLNET.EXPIRE_TIME is in place.
The following error messages are found in alert.log:
found dead dispatcher 'D001', pid = (12, 1)
The Dispatcher process core dumps and trace files are generated.
The following message might occur for dedicated connections:
[Address not mapped to object] [0x000000000]  
ORA-03135: connection lost contact
Dead Connection Detection (DCD) may have been recently enabled in this environment. Check for the existence of the SQLNET.EXPIRE_TIME parameter in the sqlnet.ora file that is local to the instance or in the listener's environment.
Sign In with your My Oracle Support account
Don't have a My Oracle Support account? Click to get started
Million Knowledge Articles and hundreds of Community platforms