Re: TDS (M$ SQL Server) in the high-latency environments

On Sat, 29 Mar 2008 06:03:01 +0300
"Fi Dot" wrote:

> Dear All,
>
> We have been struggling a lot about TDS & ODBC performance over
> high-latency connections.

I have as well.

>
> We're using MS SQL 2000 and unixODBC on Gentoo Linux to connect to it.
>

So am I. Just like that.

> Our problem is that we have a single database that is being accessed
> by multiple application servers all over the world. Sometimes network
> latency between an appserver and the database could reach one
> second!!!
>

[8<]

>
> The only reason for this behavior I could see is that if TDS does
> roundtrips to fetch the data... that's my guess... Im going to sit
> down with Wireshark to see what's going on exactly, but meanwhile....

Setting the freeTDS and unixODBC log locations and levels might help
too. Or not.

>
> Does anyone have any experience with that, or have any good pointers
> to documentation / info on that? I wasn't able to find anything
> decent on the Net :(
>

That was my experience as well.

I would suggest the freeTDS and unixODBC lists may be a place to
explore and seek help. I'm very curious as to what you may find, too.

For me, I'd say that it may be the freeTDS implementation, or unixODBC
that is at fault, somehow. I often have timeout issues with the
utilities that come with these programs when I use them from a remote
location.

Then again, it seems like the problem mostly goes away when the load on
the server is very low. Honestly, I don't have a clue.

Fortunately for me there is no latency between my appserver and the
database, but I'm stuck with that setup until I can figure out the
timing issues.

Cheers,

--
|\ /| | | ~ ~
| \/ | |---| `|` ?
| |ichael | |iggins \^ /
michael.higgins[at]evolone[dot]org