I installed a BD 12c, and every day at a certain time the BD stops working and when I want to start it again, it throws me the following error:

Error ORA-03113: end-of-file on communication channel

To work again, I have to execute the command:

alter database clear unarchived logfile group 1;

But the next day the same thing happens again. Does anyone know any definitive solution for this?

  • 1
    Instead of compromising the recoverability of your database with the above command (which you already did), start with finding the database alert log and posting its content here. The above error is typical on startup, when your archivelog location is full and new archivelogs can not be created. Maybe it is as simple as turning archivelog mode off, or scheduling a job the regularly backs up then deletes them. – Balazs Papp Oct 18 '18 at 16:28

The connection between Client and Server process was broken, however ORA-03113 is a more generic error.

For example, ORA-03113 could be signaled for any of these scenarios:

  • Server machine crashed.
  • Your server process was killed at O/S level.
  • Network problems.
  • Oracle internal errors / aborts on the server.
  • Client incorrectly handling multiple connections.


Further investigation will almost inevitably be required, however, at Oracle/Database Administrator (DBA) level:

  • Firstly check for network problems and troubleshoot Oracle SQL*Net connnectivity.
  • Look in the Oracle alert.log file for any errors.
  • Test to see whether the server process is dead and whether a trace file was generated at failure time.
  • Check for a trace file from the failed session in Oracle's USER_DUMP_DEST and BACKGROUND_DUMP_DEST directories. Does a particular statement reproduce this problem or is it random?
  • Use SQL_TRACE on the session to find the problem statement. Again does a particular statement reproduce this problem or is it random?


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