Wireshark-users: Re: [Wireshark-users] Help with troubleshooting SQL and application server communication

From: Bill Meier <wmeier@xxxxxxxxxxx>
Date: Mon, 11 Aug 2008 22:47:32 -0400

Michael Montgomery wrote:

> <snip>

if someone could help me understand a capture between a SQL database server and its front end application server. We had a company come in and analyze our network and they stated in their report that our application server is not processing SQL data being received fast enough to keep up with the rest of the application.

I take this to mean that the application server (not the SQL server) is being stated to be the bottleneck. Is this correct ?

I've been tasked to re-create this trace, after reconfiguring services to use specific port numbers, to either validate/invalidate their report by using Wireshark. After running a capture I've noticed a ton of [TCP Out-of-Order] [TCP segment of a reassembled PDU] and several [TCP Dup ACK] errors.

The small number of Dup Acks may not be a problem.

The "out-of-order" segments could be caused by a number of different reasons (not necessarily bad).

In general, this type of investigation requires someone with network expertise who can familiarize themselves with the details of your network setup.

That being said, is it possible to post an extract of the capture ? (Feel free to send it privately to me if desired).

On a broader note: I would think that the company providing the report would/should provide details (traces, response time analysis, test results, etc) to explain and substantiate their conclusions. Did they indicate the existence of a network problem ?