oracle - ORA-03113: end-of-file on communication channel after long inactivity in ASP.Net app

Question

I've got a load-balanced (not using Session state) ASP.Net 2.0 app on IIS5 running back to a single Oracle 10g server, using version 10.1.0.301 of the ODAC/ODP.Net drivers. After a long period of inactivity (a few hours), the application, seemingly randomly, will throw an Oracle exception:

Exception: ORA-03113: end-of-file on communication channel at Oracle.DataAccess.Client.OracleException.HandleErrorHelper(Int32 errCode, OracleConnection conn, IntPtr opsErrCtx, OpoSqlValCtx* pOpoSqlValCtx, Object src, String procedure) at Oracle.DataAccess.Client.OracleCommand.ExecuteReader(Boolean requery, Boolean fillRequest, CommandBehavior behavior) at Oracle.DataAccess.Client.OracleCommand.System.Data.IDbCommand.ExecuteReader()

...Oracle portion of the stack ends here...

We are creating new connections on every request, have the open & close wrapped in a try/catch/finally to ensure proper connection closure, and the whole thing is wrapped in a using (OracleConnection yadayada) {...} block. This problem does not appear linked to the restart of the ASP.Net application after being spun down for inactivity.

We have yet to reproduce the problem ourselves. Thoughts, prayers, help?

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More: Checked with IT, the firewall isn't set to kill connections between those servers.

Answer 1

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

Is the database letting you know that the network connection is no more. This could be because:

1. A network issue - faulty connection, or firewall issue
2. The server process on the database that is servicing you died unexpectedly.

For 1) (firewall) search tahiti.oracle.com for SQLNET.EXPIRE_TIME. This is a sqlnet.ora parameter that will regularly send a network packet at a configurable interval ie: setting this will make the firewall believe that the connection is live.

For 1) (network) speak to your network admin (connection could be unreliable)

For 2) Check the alert.log for errors. If the server process failed there will be an error message. Also a trace file will have been written to enable support to identify the issue. The error message will reference the trace file.

Support issues can be raised at metalink.oracle.com with a suitable Customer Service Identifier (CSI)