A Threshold of 50

Question

We are running ODP.Net 9.2.0.4, IIS 5.0, .Net Framework 1.1, ASP.Net 1.1, IE 6.0, Oracle Server and Client 9.2.0.4, all on Windows 2000 Server service pack 4.
We have discovered a curious problem when the 50th user since IISRESET (aspnet_wp restart) attempts to access certain functions in the application (not at logon, not at initial database access, only when they reach one of a couple of different functions within the application).
Test Procedure: the tester opens a new browser session, logs on with a different userid, navigates to a particular point in the application, and executes one of the offending functions. Then the next tester does the same … and so on. 50+ different userids are employed in this test.
Users 1 – 49 get to and execute the function (which is a cmdExecuteScalar or cmdExecuteReader on different tables). For these first 49, the function executes.
For the 50th and subsequent users, an error is thrown. In different test cycles we used different userids (so the 50th user was not the same userid from test to test).
If connection pooling is OFF (false), the error thrown is “ORA-12560 TNS Protocol Adapter Error”.
If connection pooling is ON (true), the error thrown is “ORA-00942 Table or View does not exist”. This error gets thrown at the 50th distinct user regardless of the min pool size setting.
Furthermore, once beyond the threshold, if we logout some of the earlier 1 – 49 userids and log back in, they still work. If we log them out and try new userids, the new ones throw the error. The original (1 – 49 pool) can still utilize the application.
On the database side, we turned-on full blown logging (lsnrctl trace 16) in an attempt to catch the error. The attempt by the 50th and subsequent user never gets to the database. The ORA errors are thrown before the round-trip from aspnet_wp to the database.
On the web server side, we are about to run another set of tests with ODP.Net tracing on. (I was not aware of this feature on our earlier tests.)
This problem is also in production. The user base is not that big, but it does accumulate past 50 users sometime during the afternoon. It usually occurs around the same time almost every day, depending on activity. Each time, the customer has to bounce IIS. This is not good.
Does anyone out there know of some configuration setting in ODP.Net, IIS, the .Net Config files, or elsewhere that could be a suspect here?

Answer 1

More information.
We set ODP.Net logging and ran through 50 users until we repated the error (again). Unfortunately it was not very illuminating to us. Perhaps someone else will find it so.
These are the lines associated with the "ORA-00942 Table or View not found" that is thrown when using connection pooling. Remember, the 1st through 49th user since aspnet_wp restart ran this query with no issue.
For the 50th (and subsequent) Logon User....
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (ENTRY) OracleConnection::Open()
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (EXIT) OracleConnection::Open()
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (ENTRY) OracleCommand::ExecuteReader()
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (ENTRY) OpsSqlExecuteReader()
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (ENTRY) OpsErrAllocCtx()
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (EXIT) OpsErrAllocCtx(): RetCode=0 Line=185
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (ENTRY) OpsSqlAllocCtx()
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (EXIT) OpsSqlAllocCtx(): RetCode=0 Line=80
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 OpsSqlExecuteNonQuery(): SQL: SELECT Request_Type_ID , Description FROM REQUEST_TYPE WHERE SPO_ID = 'C-130' ORDER BY sort_order ASC
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (EXIT) OpsSqlExecuteReader(): RetCode=-1 Line=308
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (ENTRY) OpsErrGetOpoCtx()
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (ERROR) Oracle error code=942
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (EXIT) OpsErrGetOpoCtx(): RetCode=0 Line=125
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (ENTRY) OpsSqlFreeValCtx()
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (EXIT) OpsSqlFreeValCtx(): RetCode=0 Line=154
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (ENTRY) OpsErrFreeCtx()
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (EXIT) OpsErrFreeCtx(): RetCode=0 Line=212
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (ENTRY) OpsSqlFreeCtx()
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (EXIT) OpsSqlFreeCtx(): RetCode=0 Line=105
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (ENTRY) OracleConnection::Close()
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (ENTRY) OpsConCloseProxyAuthUserSession()
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (EXIT) OpsConCloseProxyAuthUserSession(): RetCode=0 Line=488
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (ENTRY) OpsConCheckConStatus()
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (EXIT) OpsConCheckConStatus(): RetCode=0 Line=1444
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (EXIT) OracleConnection::Close()
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (ENTRY) OracleConnection::Dispose()
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (ENTRY) OpsConFreeValCtx()
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (EXIT) OpsConFreeValCtx(): RetCode=0 Line=587
TIME:2004/ 8/27-14:41:48:951 TID: 4c8 (EXIT) OracleConnection::Dispose()
Again, any help would be greatly appreciated!