Posted by Robert Klemme on 06/01/05 14:38

JENS CONSER wrote:
> Hello NG,
>
> We have a performance problem in using a client
> server solution based on MS SQL-Server 2000 through
> a VPN tunnel (via broadband internet connection).
>
> The SQL Server is running on a Windows 2003 Server
> which is configured as VPN server as well.
>
> We figured out that not the performance
> of the VPN tunnel itself is the problem,
> but the problem is the access to the MS SQL Server.
>
> We tested it by executing sql statements on the Query Analyzer
> on the VPN client (WIN XP built in) which is connected to the server
> through the tunnel.
>
> For example execution of the SELECT statement
> "select TOP 1000 * from Items" on the
> database trough the tunnel takes more than 30 times as much
> than the same execution on the server itself or within the
> server's local network.
>
> But we can make FTP downloads from our server through
> the tunnel with 600 KBit/s under same conditions
> so the bandwidth of the tunnel should not be the problem.
>
> Do you have any ideas how we can accelerate this
> or does any one has made experiences
> related to this topic?
>
> Thanks for your help!
>
> JENS

I don't think you can easily compare download speed (simple
unidirectional) with JDBC server communications (several calls back and
forth). Network latency is probably killing you. This latency might stem
from WAN and / or from encryption overhead.

You can try this

- increase fetch size for query results

- choose another select method (cursor vs. direct)

- tweak network settings to change the size of packets transferred

IMHO any DB protocol is sub optimal for wide area deployment. I'd rather
use a protocol tailored to your application's needs between client and
server, which also means you need another component on the server side
that is a client to the db and a server to your clients (middle tier).

Kind regards

robert

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