Attempted to read or write protected memory problems

Question

Hi there, we are having some issues with ODP.net. every few days after our system has been used quite a lot we get the "Attempted to read or write protected memory. This is often an indication that other memory is corrupt." errors.
I can reproduce this just by launching some threads that all make some DB calls, and after a while (took over an hour in the case) we encounter the error. It it not just one DB call causing it, looking at the logs it does appear to only be calls to 'Get' data, but just about all of them have failed at some point.
Yes we have upgraded to the latest version 11.1.0.6.20 and it still happens. Here are some stack traces, Oracle.DataAccess.Client.OpsSql.AllocSqlValCtx seems to be the most common in the stack traces though, others do occur.
at Oracle.DataAccess.Client.OpsSql.AllocSqlValCtx(OpoSqlValCtx*& pOpoSqlValCtx) at Oracle.DataAccess.Client.OracleCommand.BuildCommandText() at Oracle.DataAccess.Client.OracleCommand.ExecuteReader(Boolean requery, Boolean fillRequest, CommandBehavior behavior) at Oracle.DataAccess.Client.OracleCommand.ExecuteReader() at BUPA.HUGO.Common.DataAccessLayer.Database.StoredProcedures.ProspectSP.GetPersonProspectStoredProcedure.GetFullPersonDetailsDataReader(Int64 personId) in c:\Projects\CC.NETbuild_Hugo_Prod\Server\RF_Hugo_Services\Common\DataAccessLayer\Database\StoredProcedures\ProspectSP\GetPersonProspectStoredProcedure.cs:line 43
Sometime the top of the stack is
at Oracle.DataAccess.Client.OpsSql.CopySqlValCtx(OpoSqlValCtx* pOpoSqlValCtxSrc, OpoSqlValCtx*& pOpoSqlValCtxDst) at Oracle.DataAccess.Client.OracleParameter.PostBind_RefCursor(OracleConnection conn, OpoSqlValCtx* pOpoSqlValCtx) at Oracle.DataAccess.Client.OracleParameter.PostBind(OracleConnection conn, OpoSqlValCtx* pOpoSqlValCtx, Int32 arraySize) at Oracle.DataAccess.Client.OracleCommand.ExecuteReader(Boolean requery, Boolean fillRequest, CommandBehavior behavior) at
or
at Oracle.DataAccess.Client.OpsDac.Read(IntPtr opsConCtx, IntPtr opsErrCtx, IntPtr opsSqlCtx, IntPtr& opsDacCtx, OpoSqlValCtx* pOpoSqlValCtx, OpoMetValCtx* pOpoMetValCtx, OpoDacValCtx* pOpoDacValCtx) at Oracle.DataAccess.Client.OracleDataReader.Read()
Does anyone have any ideas? I saw some older post just asking people to try the new version (which we have). Any help on this matter would be great. We are having trouble figuring out if it is something we are not doing correctly or if there is a bug in ODP.NET.
Thank you,
Luke

Answer 1

Hello,
I've got exactly the same problem. We're using ODP.NET 10g R2 10.2.0.3.02 with RAC database. I found that this error only occurs after a Failover event.
My application is .NET 3.0 WPF app.
I'm able to reproduce this error at any time.
Please have a look at some source code:
//opening OracleConnection:
theConn.Open();
theConn.Failover += new OracleFailoverEventHandler(theConn_Failover);
// handling the Failover event as stated in the docs:
static FailoverReturnCode theConn_Failover(object sender, OracleFailoverEventArgs eventArgs)
Logging.LogInfo("DB-FailoverEvent: " + eventArgs.FailoverEvent.ToString() + " - Type: " + eventArgs.FailoverType.ToString());
switch (eventArgs.FailoverEvent)
case FailoverEvent.Begin:
Logging.LogInfo("FailoverEvent.Begin - Failover is starting");
Logging.LogInfo("FailoverType = " + eventArgs.FailoverType.ToString());
break; // TODO: might not be correct. Was : Exit Select
case FailoverEvent.End:
Logging.LogInfo("FailoverEvent.End - Failover was successful");
break; // TODO: might not be correct. Was : Exit Select
case FailoverEvent.Reauth:
Logging.LogInfo("FailoverEvent.Reauth - User reauthenticated");
break; // TODO: might not be correct. Was : Exit Select
case FailoverEvent.Error:
Logging.LogInfo("FailoverEvent.Error - Failover was unsuccessful");
// Sleep for 3 sec and Retry
Thread.Sleep(3000);
return FailoverReturnCode.Retry;
case FailoverEvent.Abort:
Logging.LogInfo("FailoverEvent.Abort - Failover was unsuccessful");
break; // TODO: might not be correct. Was : Exit Select
default:
Logging.LogInfo("Invalid FailoverEvent : " + eventArgs.FailoverEvent.ToString());
break; // TODO: might not be correct. Was : Exit Select
// comment following lines will not raise an error
if (connect2DB())
return FailoverReturnCode.Success;
else
return FailoverReturnCode.Retry;
And here's the source for checking DB-connection:
private static bool connect2DB()
if (null == myConn)
myConn = openOracleConnection();
if (null == myConn)
Thread.Sleep(5000);
return false;
try
if ((myConn.State == ConnectionState.Broken) || (myConn.State == ConnectionState.Closed))
myConn = openOracleConnection();
String sql = "SELECT 1 FROM dual";
using (OracleCommand cmd = new OracleCommand())
cmd.Connection = myConn;
cmd.CommandText = sql;
cmd.CommandTimeout = 2;
using (OracleDataReader dr = cmd.ExecuteReader())
dr.Read();
catch (Exception ex)
Logging.LogError(ex);
closeOracleConnection(myConn);
myConn = openOracleConnection();
setDBConnState();
if (null != myConn)
if ((myConn.State == ConnectionState.Broken) || (myConn.State == ConnectionState.Closed))
return false;
else
return true;
else
return false;
When I don't call "connect2DB()" in the failover event handler then everything is fine - otherwise oops the error occurs after approx. 14 hours after application runtime.
Regards
Sven