[mapserver-users] Using Fast CGI with MapServer to alleviate poor performance

[Guillaume Sueur]

Hi John,

Could you try to set your map projection with its EPSG code instead of
the proj string, and see what happens ?

Regards,

Guillaume

John Westwood a écrit :
> Hi Everybody,
> 
> I am attaching  a cut down version of my html, javascript and map files. On our server the EmbeddedMap.js lives in the OpenLayers directory and is used by gbhgis_openlayers.html.
> 
> The test address http://148.197.8.119/gbhgis_openlayers.html . This is just a test server so please don't tell the whole World about it! :)
> 
> There are four layers, 2 x raster (europe 1940s, WMS and MapServer) and 2 x vector / raster (Digital Chart of the World, WMS and MapServer) .
> 
> A problem with using the OpenLayers.MapServer method is that the (1) The raster colours are messed up and (2) Anti-aliasing is not being done on the vector layers. I don't know why this is.
> 
> Regards,
> 
> John Westwood
> 
> 
>>>> Stephen Woodbridge <woodbri at swoodbridge.com> 18/09/08 9:08 PM >>>
> 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" <pramsey at cleverelephant.ca> 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
>> <John.Westwood at port.ac.uk> 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
>>
>> _______________________________________________ mapserver-users
>> mailing list mapserver-users at lists.osgeo.org 
>> http://lists.osgeo.org/mailman/listinfo/mapserver-users
> 
> 
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