Connection request timed out after 15 seconds

It seems that #126 has not been fixed for some cases even after Oracle.ManagedDataAccess.Core v2.19.101 release.

Oracle.ManagedDataAccess.Client.OracleException (0x80004005): Connection request timed out
   at OracleInternal.ConnectionPool.PoolManager`3.Get(ConnectionString csWithDiffOrNewPwd, Boolean bGetForApp, OracleConnection connRefForCriteria, String affinityInstanceName, Boolean bForceMatch)
   at OracleInternal.ConnectionPool.OraclePoolManager.Get(ConnectionString csWithNewPassword, Boolean bGetForApp, OracleConnection connRefForCriteria, String affinityInstanceName, Boolean bForceMatch)
   at OracleInternal.ConnectionPool.OracleConnectionDispenser`3.Get(ConnectionString cs, PM conPM, ConnectionString pmCS, SecureString securedPassword, SecureString securedProxyPassword, OracleConnection connRefForCriteria)
   at Oracle.ManagedDataAccess.Client.OracleConnection.Open()
   at System.Data.Common.DbConnection.OpenAsync(CancellationToken cancellationToken)
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.OpenDbConnectionAsync(Boolean errorsExpected, CancellationToken cancellationToken)

Elapsed when this error happens: 15.001 15.031 15.179 15.156 15.107 and so on a bit above 15 seconds timeout. The connection pool does not appear to be exhausted. We don’t explicitly size it, so I’m pretty sure the default is 100.

The example output from OracleConnection.Dump when this happened:

(DUMP)
(CP) =================================
(CP) Data Source=(DESCRIPTION=(ENABLE=BROKEN)(LOAD_BALANCE=off)(FAILOVER=on)
(TRANSPORT_CONNECT_TIMEOUT=10)
(ADDRESS=(PROTOCOL=tcp)(HOST=<address1>)(PORT=1526))
(ADDRESS=(PROTOCOL=tcp)(HOST=<address2>)(PORT=1526))
(CONNECT_DATA=(SERVICE_NAME=<name>)(FAILOVER_MODE=(TYPE=session)(METHOD=basic))));
User Id=<id>;Password=;
(CP) pmid=
55059565(CP) =================================
(CP) <name> , <name2>:
(CP)   list  (count:1) : (2962:4287:T:F:F:F:N:<name>::<name2>)

(CP)   queue (count:0) : 

Names were replaces.

[alexkeh]

The timeout occurs as managed ODP.NET is looking for libraries it expects in .NET FW, but is not part of .NET Core. Since the library is not found, the connection times out. There’s an ER (35402151) to improve the error message so that the app knows it has the wrong ODP.NET provider type loaded.

[monty241]

It seems that “connection timeout” also occurs when using a wrong version of the assembly. In our case, instead of 3.1.21.1 (.net core), the error occurred when due to a build error either 3.21.100 or (.net framework) 4.122.21.1 DLL were present. Somewhat confusing is that the managed driver DLL of Oracle.ManagedAccess.Core nuget package is also Oracle.ManagedAccess.dll.

A clear error occurs solely when the Oracle.ManagedDataAccess.dll is not present.

Maybe Oracle internally calls some code for a number of times and even with internal errors always returns a generic “connection timeout” from an exception handler?

Fix was to use the correct version of the DLL.