System.Data.OleDb.OleDbConnectionInternal..ctor: Unspecified error

After several hours (~6 hours Win7 64bit, ~24hours WinXP) of running multi-threaded (.NET Framework 3.5 SP1 WinForms) desktop application using .mdb files as backend I'm getting the following runtime error:

Exception -> Unspecified error

StackTrace ->

at System.Data.OleDb.OleDbConnectionInternal..ctor(OleDbConnectionString constr, OleDbConnection connection)

at System.Data.OleDb.OleDbConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningObject)

at System.Data.ProviderBase.DbConnectionFactory.CreateNonPooledConnection(DbConnection owningConnection, DbConnectionPoolGroup poolGroup)

at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection)

at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory)

at System.Data.OleDb.OleDbConnection.Open()

at NetworkManager.SearchInputFileHandler.GetInputRows(SearchProgramTypeEnumeration programType, Int32 startRowNum, Int32 rowsQty, Boolean setupInProgress, Boolean filterOutUninitializedRows)

It looks like this is an OleDbProvider bug.

Have you seen/experienced something like that?

Context:

(1) I do exclu开发者_Go百科sively use

using (OleDbConnection cnn = new OleDbConnection("{{mymdbConnectionStringHere}}")) {

cnn.Open();

...

}

(2) I do use IN clause in some select SQL expressions to point to external MDB tables.

I guess the issues is caused by case (2). Although that's still a hypothesis here to check (some code fixes are needed in the core code of my application, and I'm considring now will that be worth fixing, or I should better switch to MS SQL backend.)

Thank you.

---

Was there any progress in finding out the solution for this issue or more stabe workaround?

I have similar problem in ASP.NET application with reading Excel file. It is only visible in production environment where many users attempt to process different XLS files on the server side. After recycling IIS service at night there are around ~200 requests (to open excel) that hang JET engine. The problem is that all subsequent attempts fail so retry logic wouldn't help much. Only IIS reset heals the problem.

From the investigation I've made there are several options to take:

1. Switch to other library to read XLS files: Excel OLE Automation - requires Excel to be installed on server and having many requests would create many instances of Excel process that's not acceptable. 3rd party library - are any of these free?
2. Move excel processing to separate process. Exchange data with some other format as XML.
3. Use some sort of smart handling to control number of OLEDB open and closes going on in the process.

Any thoughts?

---

I had the same problem. Recyling only the application pool in IIS worked for me.

---

I have written sample test application - the issue is caused by a bug somewhere in the internals of .NET System.Data.OleDb.

Test VS2008 SP1 solution is published here: System.Data.OleDb bug demonstration sample.