John Westwood wrote:
Hi Paul and other MapServer Gurus,
I have discovered a huge speed increase by using OpenLayers.MapServer
(native) layers instead of OpenLayers.WMS layers. It is about ten
times faster, I do not exaggerate. Why is WMS so slow? I have read
that MapServer is a fast WMS server, have I done something wrong for
it not to be?
What do you think could be the problem?
You might want to check that you are comparing apples and apples. I
would expect WMS to be a little slower because there is some overhead to
query the server before actually making the image request.
Do you have ratio set the same for both layers?
What versions of Mapserver and OpenLayers are you using?
Can you post a URL that has the two layers present in the layer switch
so we can look at the requests and how your have it configured? Or post
the HTML so we can look at. In fact you might want to post the HTML to
the openlayers list and as the question there first, to make sure you
have equivalent requests between WNS and Mapserver.
-Steve W
I will give it some thought tomorrow.
John
"Paul Ramsey" <[EMAIL PROTECTED]> 17/09/08 5:15 PM >>>
John,
The idea that CGI is naturally a much slower situation than a
long-running process is a bit of a red herring in the case of
Mapserver, and I say that as someone who is anal retentive about
these things. Unless your Mapserver installation has some naturally
latent components (database connections, primarily) you'll find that
moving from CGI to FastCGI is worth about 15ms per request.
On Wed, Sep 17, 2008 at 8:40 AM, John Westwood
<[EMAIL PROTECTED]> wrote:
The reason I am trying to get MapServer to work with fast_cgi is
because I am experiencing poor performance with OpenLayers. I
believe that OpenLayers starts a new MapServer instance for each
tile request, thus causing an unnecessary overhead. Am I correct?
Yes and no. If you are experiencing noticeably poor performance (you
can actually *see* it being slow) the only place that the CGI
overhead could be the cause is if you're connecting to Oracle or SDE
for some of your layers. If that's not the case, look elsewhere
first, the very small gains you will receive from moving to FastCGI
will not change your underlying problem.
Paul
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