Win7 vs XP Network/Database Access Puzzle

[Galant]

Hi Guys,

Whilst reviewing a new system I've stumbled onto something of a mystery situation and I'm having trouble pin-pointing the cause. I'm starting to run-out of things to try and was wondering if any of you might be able to offer some insight.

Here's the setup:

We have a Windows Server 2003 tower which hosts a database (DBISAM).
Then we have three networked machines each running client programs which access that database - one is running Windows 7 embedded and the other two are XP machines.

One of the functions of the client software is to perform a text/keyword search for items in the database (think of a shop-front till where you can type in a word and it will retrieve any products which correspond). The odd situation I have is that the Win7 machine is performing noticeably slower than the XP machine. The exact same search might take the XP machine 2-3 seconds whereas it will take the Win 7 machine 10 seconds. In some cases I've seen much longer search times which become unacceptable.

Now, in terms of hardware, the Windows 7 machine is far superior - i5 processor, 4GB RAM etc. (Although the program is quite light and really none of this is related to hardware/memory).

So, what I am trying to understand is why an XP machine might be able to perform that network database search faster than a Win 7 machine. I've matched the networking settings although Windows 7 has a lot more options than XP does. I've been thinking it is either something to do with how 7 is handling networking, or talking to the database.

Does anyone have insight into why an XP machine might communicate and search faster?

Thanks,

G.

[mycarsavw]

Could it be something to do with TCP/IP auto-tuning introduced from Vista onwards?

http://www.sevenforums.com/network-s...tml#post654207

The link doesn't specifically mention slow SQL access but it has been noted as one of the reasons.

[scaryjim]

Afraid I don't know anything about DBISAM, but I'd be surprised if the search was running on the client hardware - any sanely developed client/server DB has the search running on the server and simply handing off the results to the clients. So either the Win 7 version is requesting the search differently so the server is taking longer to process it, or the results are taking much longer to transfer through the networking stack. It might be an idea to log server performance under controlled queries from the three different clients to see which component is behaving differently. That would be a good place to start narrowing down the search between hardware peformance and network performance...

[Galant]

mycarsavw - I'll take a look at the autotuning. Thanks.

scaryjim - It does run the search on the server. Any recommendations on software for logging the server performance or would Windows own tools suffice?

I can also specify the following:

If I reboot all machines and then open the client software only on the Win7 machine the search function runs rapidly. As soon as I open up any other client the search speed is reduced. This is actually true for all clients, however, it is the Win7 machine which suffers the most.


Thanks,

A.

[Galant]

Update - I think I might have cracked it - although missing the exact cause.

The following are/were all possible issues:

Auto-Tuning (as per mycarsavw) - Disabled it.
Link Local Multicast Name Resolution (LLMNR) - Disabled it.
Advanced Network Adapter Features - Disabled any and all that could be disabled.
Opportunistic Locking (OpLocks) - Needs registry entries creating/editing to enable or disable it.

I disabled the features one by one in the above order and the search speed didn't improve until after I disabled all the advanced features, so it could be that it was one of the feature in there that was/is the culprit or a combination. Essentially, Win7 has a lot of 'helpful' features that XP/Server2003 don't know what to do with, resulting in a net slow down in communication.

Oplocking looked like it could/should have been the issue in terms of the clients affecting one another, however, even though there is some slight slowing that occurs when the clients are run in combination, I found the client searches went a lot faster with the caching that oplocking provides rather than without it.

Essentially, it looks like a change in the way the database works (rendering oplocking irrelevant), and avoiding the Win7/XP or 2003 combination, should result in even faster performance, but that remains to be seen.

For now, things seem to be quick and stable.

Thanks for the help!