[mapserver-users] Mapserver/PostGIS Faster Initial Load Time

[Donald Kerr]

Jeff,

Great tip!

My deployment uses a full compressed build of the openlayers.js file with
some changes to vml.js (uses vml textpath - for <= IE8) and svg.js (uses
text rotation - for Chrome and Firefox). This file comes in at 927 KB.

I created a custom compressed build of the openlayers.js file, again
including the vml and svg changes. The new file comes in at 443 KB; a very
significant drop in size.

Both files were built using the latest, hot off the press,
OpenLayers-2.12-rc6.

Prior to creating and using the new, smaller openlayers.js file, I tested
the time to get the first raster image tile from boot up with the larger
file which was 16 seconds. I did a one click zoom to the first layer that
has PostGIS sitting behind it and that took a further 8 seconds. After that
initial load of both layer types, everything is speedy with very little
delay at all.

I then substituted the new, smaller openlayers.js file and repeated the
process from boot up. Low and behold, I get exactly the same results: 16
seconds then 8 seconds. Whilst there is probably a time saving in terms of
milliseconds, the perceptional difference is nil.

However, I do agree that the smaller openlayers.js file is the way to go in
terms of reducing unnecessary initial traffic and also having less
javascript in memory; something that will no doubt aid Internet Explorer
speed-wise as that particular platform is chronic at best.

Thanks again for the tip.

Regards,

Donald



-----Original Message-----
From: mapserver-users-bounces at lists.osgeo.org
[mailto:mapserver-users-bounces at lists.osgeo.org] On Behalf Of Jeff McKenna
Sent: 08 June 2012 16:10
To: mapserver-users at lists.osgeo.org
Subject: Re: [mapserver-users] Mapserver/PostGIS Faster Initial Load Time


On 12-06-06 4:35 PM, Donald Kerr wrote:
> Basically my mapping setup is, from client to server, Openlayers 
> WMS/WFS (Internet Explorer on XP Pro SP3) - Mapserver CGI - Shapefile 
> (Tiffs) or PostGIS (XP Pro SP3 - IIS & FastCGI).
> 
>>From boot up, the initial, or first load of maps, takes up to 15 
>>seconds.
> After that, it flies along fine.
> 
> I've tried pre-loading in a hidden browser instance but that didn't 
> work. I cannot get that initial load time down at all.
> 
> Any tips to reduce the time taken for the first load of the software: 
> Specifically Mapserver whether it's creating the map from PostGIS or 
> the shapefile (Tiffs).

I can give my experiences here.  I have a very slow server that I use for
client demos, and I very often hit this exact same issue (my
OpenLayers/MapServer WMS/WFS application takes very long to load initially,
then zooms along).  In my case, the long initial load is always due to the
large lib/OpenLayers.js file; I solve this by generating an
'OpenLayers-lite.js' file (through the instructions at
http://docs.openlayers.org/library/deploying.html).

I hope that helps someone along the way.

Have a nice weekend all.

-jeff



-- 
Jeff McKenna
MapServer Consulting and Training Services http://www.gatewaygeomatics.com/


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