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Posted by Erland Sommarskog on 06/02/05 23:39
JENS CONSER (jens@e-sistrum.com) writes:
> we did the ftp-test only to proof that the tunnel speed is not
> the reason and to see the current performance of the
> tunnel. the vpn connection is shown on the network monitor
> on the server with 28kbit/s and on the client with 100mbit/s
> but both has nothing to do with the real performance.
> especially the server speed is a real fake.
> and also in a lan the speed is not real 100 mbit/s
> despite it is shown for the network adapter.
> so approx. 600 kbit/s should be the maximum performance
> of the tunnel from our client (in egypt) to the server (in usa)
OK, but I assumed that there is some underlying physical connection,
and this one should have some speed as labeled by the service provider.
> when i executed the sql statement it takes 5 seconds
> on the lan and more than 3 minutes through the tunnel.
I don't know what sort of statement you executed, but does response
time change if you first say SET NOCOUNT ON?
Also, if you are in Query Analyzer, do you get different results for
grid mode and text mode?
> i tend more to roberts opinion that the network latency is
> the reason and the bidirectional communication,
> although i can't image that a simple select causes
> so much communication.
Looking at the application, it may matter what access methods you
use. Server-side cursors could have quite some penalty here.
> i think i will try first to increase the packet size like robert said,
> does anyone know how to do it in windows, before i waste
> time to serach for it?
I don't know about Windows, but you can set the packet size for
SQL Server communication when you connect. For instance, in
Query Analyzer you find this under Tools->Options->Connection.
It's also possible to set a different default packet size for
the server with sp_configure.
--
Erland Sommarskog, SQL Server MVP, esquel@sommarskog.se
Books Online for SQL Server SP3 at
http://www.microsoft.com/sql/techinfo/productdoc/2000/books.asp
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