ORA-03113 Error Message End-of-File on Communication Channel
Oracle errors can often fall into two large categories: errors caused by syntax error and misappropriation and connection errors between servers. The latter can prove quite frustrating in that there can often be a number of places to search in order to decipher just where exactly the error message is emanating from. An ORA-03113 is, unfortunately, one of these errors. With that said, there are several steps to be taken that can manage and prevent this type of Oracle error from slowing you down.
The source of an ORA-03113 is a broken connection between Client and Server process, a blanket end-of-file on a communication channel error. When the error occurs during the process of connecting, it suggests a lost connection that is similar to a timeout. The error could be signaled for a multitude of reasons, such as a server machine crashing, network issues, internal Oracle errors on the server, your server process being ended at the operating-system level, or a Client having issues handling multiple connections. The error also can occur in conjunction with other errors, such as the ORA-01012 (not logged on), ORA-01041 (hostdef extension does not exist), or ORA-03114 (not connected to Oracle). While it can feel overwhelming to have multiple errors triggered at once, these can actually be a first path to correcting all the errors by providing a focus of where the problem is stemming from.
Due to the vast array of complications that define this catch-all error, it would be best to go through some simple steps to resolve an ORA-03113 on your own. You can start by checking your network and troubleshooting the SQL*Net connection. To do this, check by pinging via the IP address and the DNS name. You can then try sending telnet to the IP address on port 152, and check connectivity with a TNS ping using your TNS service name. Lastly, you can check your connection through a few further methods within SQL*Plus.
If you are unable to locate connection problems through SQL*Net, you can next look into the alert.log file for potential errors. In the event of a server process failure, an error message will pop up here that gives a trace file in order to identify the problem. Another route is to check if the server process had ended and whether or not a trace file was signaled at the time of its failure. This could give an indication of a possible location to fix an ORA-03113.
One of the most frequently reported causes of an ORA-03113 results from the presence of a firewall. This can end the Oracle connection after a certain period of time. For this, utilize a sqlnet.expire_time parameter. What this will do is enable the server to detect a dead connection after a specified period of time, and if not connected the server process will exit. This will effectively render the firewall to consider that the connection is still live.
An ORA-03113 is one of a more difficult error to fix simply due to the wide stretch of problems it can indicate. Being cognizant of how your networks operate and what types of firewalls may or may not be present can give you a jump start on managing this type of error. It also helps to have regular communication with your network administrator, as well as a working closely with a reputable Oracle consultant to help navigate the waters of some of the more complex network-generated issues in Oracle.