Multiple Simultaneous SQL Connection Timeouts In Multithreaded Windows Service

Question

I have a multithreaded Windows Service I\'ve developed with VS 2010 (.NET 4.0) which can have anywhere from a few to a few dozen threads, each retrieving data from a slow se

Answer 1

According to the MSDN Blog post just created today (hooray for Google!):

Microsoft has confirmed that this is a problem in the current release of ADO.NET. This issue will be fixed in ADO.NET version, ships with Visual Studio 2011.

In the meantime, we request to use the following workarounds:

1. Increase the connection string timeout to 150 sec. This will give the first attempt enough time to connect( 150* .08=12 sec)

2. Add MinPool Size=20 in the connection string. This will always maintain a minimum of 20 connections in the pool and there will be less chances of creating new connection, thus reducing the chance of this error.

3. Improve the network performance. Update your NIC drivers to the latest firmware version. We have seen network latency when your NIC card is not compatible with certain Scalable Networking Pack settings. If you are on Windows Vista SP1 or above you may also consider disabling Receive Window Auto-Tuning. If you have NIC teaming enabled, disabling it would be a good option.

The post itself is an interesting read, talking about a TCP/IP connection retry algorithm. And kudos to all the folks who said "hey this looks like it's related to mirroring..."! And note the comment about this being "because of slow response from SQL Server or due to network delays".

UGH!!!

Thanks to everyone who posted. Now we must all ask for a patch to the .NET Framework (or some other ADO.NET patching mechanism), so we don't have to wait for (and buy) Visual Studio 11...