SqlDependency.Start KeyNotFoundException - Possible Bug

[Guest]

I'm working heavily with query notifications in SQL Server 2005 and I'm now
getting the following exception:

System.Collections.Generic.KeyNotFoundException: The given key was not
present in the dictionary.

This was working for quite a while and then it stopped. At first, the
exception was intermittent, but now it's permanent. The exception is
happening deep inside of a System.Data.dll in a class called
SqlDependencyProcessDispatcher in a method defined as follows:

private bool Start(string connectionString, out string server, out
DbConnectionPoolIdentity identity, out string user, out string database, ref
string queueService, string appDomainKey, SqlDependencyPerAppDomainDispatcher
dispatcher, out bool errorOccurred, out bool appDomainStart, bool useDefaults)

It looks like the method is checking a dictionary for particular key; then,
if it's found, it retrieves the item from the dictionary. Looking at
Reflector it appears that this lookup may not be threadsafe. It has a few
code blocks inside structured like this:

if (!this._sqlDependencyPerAppDomainDispatchers.ContainsKey(appDomainKey))
{
lock (this._sqlDependencyPerAppDomainDispatchers)
{
this._sqlDependencyPerAppDomainDispatchers[appDomainKey] =
dispatcher;
}
}

These should probably be using
sqlDependencyPerAppDomainDispatchers.TryGetValue instead or should move the
lock to the outside of the if statement.

No one on the Internet seems to have ever encountered this.

Two partial stack traces appear below. They're partial in that I've
ommitted a
long set of calls from our interal app framework that are orthogonal to the
problem.

The NT user making these calls is a local administrator on the database
server. The calls work a lot of the time, but break and seemingly random
moments.

We use a preconfigured SQL Server Service Broker Queue named
QueryChangeMessages and a service called QueryChangeNotifications.

Please help.

One stack trace looks like this:

[KeyNotFoundException: The given key was not present in the dictionary.]
SqlDependencyProcessDispatcher.Start(String connectionString, String
queue, String appDomainKey, SqlDependencyPerAppDomainDispatcher dispatcher) +0
System.Data.SqlClient.SqlDependency.Start(String connectionString, String
queue, Boolean useDefaults) +672
System.Data.SqlClient.SqlDependency.Start(String connectionString, String
queue) +7

Nvidia.PolicyInjection.CallHandlers.SqlDependencyConnection.StartInternal()
+103

[DataException: An error occurred while calling
ConfigurationManagement.Start for connection string named
ConfigurationManagement on SQL Server Service Broker Queue
QueryNotificationQueue.]
....

Another stack trace looks like this:

Server stack trace:
at System.ThrowHelper.ThrowKeyNotFoundException()
at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
at
SqlDependencyProcessDispatcher.SqlConnectionContainer.ProcessNotificationResults(SqlDataReader reader)
at
SqlDependencyProcessDispatcher.SqlConnectionContainer.SynchronouslyQueryServiceBrokerQueue()
at
SqlDependencyProcessDispatcher.SqlConnectionContainer..ctor(SqlConnectionContainerHashHelper hashHelper, String appDomainKey, Boolean useDefaults)
at SqlDependencyProcessDispatcher.Start(String connectionString, String&
server, DbConnectionPoolIdentity& identity, String& user, String& database,
String& queueService, String appDomainKey,
SqlDependencyPerAppDomainDispatcher dispatcher, Boolean& errorOccurred,
Boolean& appDomainStart, Boolean useDefaults)
at SqlDependencyProcessDispatcher.Start(String connectionString, String
queue, String appDomainKey, SqlDependencyPerAppDomainDispatcher dispatcher)
at
System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr
md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext,
Object[]& outArgs)
at
System.Runtime.Remoting.Messaging.StackBuilderSink.PrivateProcessMessage(RuntimeMethodHandle
md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext,
Object[]& outArgs)
at
System.Runtime.Remoting.Messaging.StackBuilderSink.SyncProcessMessage(IMessage msg, Int32 methodPtr, Boolean fExecuteInContext)

Exception rethrown at [0]:
at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage
reqMsg, IMessage retMsg)
at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData&
msgData, Int32 type)
at SqlDependencyProcessDispatcher.Start(String connectionString, String
queue, String appDomainKey, SqlDependencyPerAppDomainDispatcher dispatcher)
at System.Data.SqlClient.SqlDependency.Start(String connectionString,
String queue, Boolean useDefaults)
at System.Data.SqlClient.SqlDependency.Start(String connectionString,
String queue)
....